Delayed skeletal maturation has been long accepted as a correlate of mental retardation. Three hundred mentally retarded children were examined for skeletal age and failed to show any overall delay of bone age as compared to chronological age. Further, birth weight was found to be unrelated to bone age maturity. Children with severe levels of retardation displayed significant delay in bone development only when profound physical disability was also present. In eight diagnostic categories of mental retardation, only those with metabolic syndromes showed any significant delay in skeletal system maturation. Conversely, mongoloid children showed a larger-than-chance percentage of advanced bone maturation. Skeletal measures therefore are perhaps more reflective of etiological states than of diagnostic classifications in mental retardation.
BACKGROUND—Submicroscopic subtelomeric chromosome defects have been found in 7.4% of children with moderate to severe mental retardation and in 0.5% of children with mild retardation. Effective clinical preselection is essential because of the technical complexities and cost of screening for subtelomere deletions.
METHODS—We studied 29 patients with a known subtelomeric defect and assessed clinical variables concerning birth history, facial dysmorphism, congenital malformations, and family history. Controls were 110 children with mental retardation of unknown aetiology with normal G banded karyotype and no detectable submicroscopic subtelomeric abnormalities.
RESULTS—Prenatal onset of growth retardation was found in 37% compared to 9% of the controls (p<0.0005). A higher percentage of positive family history for mental retardation was reported in the study group than the controls (50% v 21%, p=0.002). Miscarriage(s) were observed in only 8% of the mothers of subtelomeric cases compared to 30% of controls (p=0.028) which was, however, not significant after a Bonferroni correction. Common features (>30%) among subtelomeric deletion cases were microcephaly, short stature, hypertelorism, nasal and ear anomalies, hand anomalies, and cryptorchidism. Two or more facial dysmorphic features were observed in 83% of the subtelomere patients. None of these features was significantly different from the controls. Using the results, a five item checklist was developed which allowed exclusion from further testing in 20% of the mentally retarded children (95% CI 13-28%) in our study without missing any subtelomere cases. As our control group was selected for the "chromosomal phenotype", the specificity of the checklist is likely to be higher in an unselected group of mentally retarded subjects.
CONCLUSIONS—Our results suggest that good indicators for subtelomeric defects are prenatal onset of growth retardation and a positive family history for mental retardation. These clinical criteria, in addition to features suggestive of a chromosomal phenotype, resulted in the development of a five item checklist which will improve the diagnostic pick up rate of subtelomeric defects among mentally retarded subjects.
Keywords: submicroscopic subtelomeric rearrangements; clinical preselection; checklist; chromosome deletion.
As the infant mental health field has turned its focus to the presentation, course and treatment of clinically significant mental health disorders, the need for reliable and valid criteria for identifying and assessing mental health symptoms and disorders in early childhood has become urgent. In this paper, we offer a critical perspective on diagnostic classification of mental health disorders in young children. We place the issue of early childhood diagnosis within the context of classification of psychopathology at other ages and describe, in some detail, diagnostic classifications that have been developed specifically for young children included DC:0-3, a diagnostic classification for mental health symptoms and disorders in infant, toddlers, and preschoolers. We will briefly outline the role of diagnostic classification in clinical assessment and treatment planning. Lastly, we will review the limitations of current approaches to the diagnostic classification of mental health disorders in young children.
psychopathology; diagnosis; infant mental health; nosology; DC:0-3R
Psychomotor retardation is a central feature of depression which includes motor and cognitive impairments. Effective management may be useful to improve the classification of depressive subtypes and treatment selection, as well as prediction of outcome in patients with depression. The aim of this paper was to review the current status of knowledge regarding psychomotor retardation in depression, in order to clarify its role in the diagnostic management of mood disorders. Retardation modifies all the actions of the individual, including motility, mental activity, and speech. Objective assessments can highlight the diagnostic importance of psychomotor retardation, especially in melancholic and bipolar depression. Psychomotor retardation is also related to depression severity and therapeutic change and could be considered a good criterion for the prediction of therapeutic effect. The neurobiological process underlying the inhibition of activity includes functional deficits in the prefrontal cortex and abnormalities in dopamine neurotransmission. Future investigations of psychomotor retardation should help improve the understanding of the pathophysiological mechanisms underlying mood disorders and contribute to improving their therapeutic management.
The diagnosis of childhood psychosis raises a host of unresolved problems, despite the Diagnostic and Statistical Manual Of Mental Disorders, 4th edition, Text Revision (DSM-IV-TR) giving identical symptoms and definitions for children, adolescents, and adults. The fantasy lives of children, and issues of developing language and cognition (including retardation), all impair diagnostic accuracy, particularly when differentiating between childhood-onset schizophrenia (COS) (≤12 years), bipolar affective disorder, major depressive disorder, and even obsessive-compulsive disorder and attention-deficit/hyperactivity disorder: the catch-all classification, psychosis not otherwise specified (PNOS), is always available for conundra that prove unsolvable. Typical if nonpathognomonic features include neurocognitive difficulties. Multiple screening instruments and specialized versions of semistructured diagnostic interviews are available. Although smooth-pursuit eye-tracking movements may prove a genetic marker for COS, etiologies are likely to be oligogenetic rather than related to a single gene. No specific biological markers or neuroimages have been identified. As such, psychoses may be indicative of a more general pattern of brain dysfunction. Drug treatments are largely based on the adult literature because of a dearth of controlled data below age 18. There are still no rigorous studies of psychosocial treatments and psychotherapy specific to childhood psychosis.
childhood-onset schizophrenia; diagnosis; psychosis in children; psychopharrnacological treatment; psychosocial treatment
One hundred and sixty six children attending educationally subnormal/mild (ESN/M) schools were karyotyped as part of a project investigating the aetiology of mild mental retardation. Nine had significant chromosome abnormalities. Five of six children identified during the survey had no dysmorphic features--47,XXY (two), 48,XXYY, 46,XX 15q-, and 46,XX,t(X;19). One dysmorphic boy had a balanced translocation--46,XY,t(3;15). Three were already known--47,XX+21 (two) and 46,XY, 14q+. We suggest that routine karyotyping of children with mild mental retardation be considered.
A diagnostic survey was undertaken of children aged 11 to 19 years in Tameside with severe learning difficulties (intelligence quotient less than or equal to 50). Eighty-two children were identified and their medical records reviewed. A specific diagnosis for the retardation was documented in 25 (30%) of the children, 18 of whom had Down's syndrome. A probable aetiology or a disorder of unknown aetiology had been identified in a further 21 (26%) children. To confirm the existing diagnosis, identify new diagnoses, and offer genetic counselling, the parents of 63 children were offered detailed reassessment of their child. Fifty three children were reviewed, and a specific disorder identified in 25 out of 31 previously undiagnosed children. The most frequent diagnoses made were fragile X syndrome and Rett's syndrome. On completion of the survey, 61 of the 82 children (74%) had a specific diagnosis or probable aetiology identified, 12 (15%) had associated disorders such as cerebral palsy, and in only nine of the 82 children (11%) were there no clues at all to the cause of their retardation.
A register of children with cerebral palsy born to mothers resident in the Mersey region from 1966 to 1977 was compiled from health service records. Frequency distributions and prevalences of birth weight and gestational age differed for those with hemiplegia, diplegia, and quadriplegia. In particular, the children with diplegia showed a bimodal frequency distribution. Children of normal birth weight with diplegia had a higher prevalence of severe mental retardation than those of low birth weight. These differences may be due to survival bias and may not be of aetiological importance. Furthermore, the mothers of diplegic infants had a significantly higher proportion of spontaneous abortions, stillbirths, and low birthweight infants in their obstetric history. This suggests that prenatal factors predominate in the aetiology of diplegia.
The magnitude of the problem of mental retardation in our country hardly needs any exaggeration. The psychological burden that these parents carry has been varied. The present study was undertaken to delineate the psychological problems of parents of mentally retarded children and to establish whether these problems were more prevalent in the parents of mentally retarded children than in the parents of normal children. The material comprised of three groups of subjects: The first group comprised of parents of twenty students of a school for mentally handicapped children; the second group comprised of parents of ten mentally retarded children who were not institutionalised or attended any special school for mentally retarded in the past: the third group comprised of parents of twenty normal school going children. The results of the study conclusively proved that the parents of mentally retarded children had a higher prevalence of psychological morbidity than the parents of normal children. The commonest psychiatric disorder was Dysthymia followed by Generalised Anxiety Disorder and Moderate Depression.
Psychological morbidity; mental retardation; general health questionnaire (GHQ)
Recent studies have shown that cryptic unbalanced subtelomeric rearrangements contribute to a significant proportion of idiopathic syndromic mental retardation cases. Using a fluorescent genotyping based strategy, we found a 10% rate of cryptic subtelomeric rearrangements in a large series of 150 probands with severe idiopathic syndromic mental retardation and normal RHG-GTG banded karyotype. Fourteen children were found to carry deletions or duplications of one or more chromosome telomeres and two children had uniparental disomy. This study clearly shows that fluorescent genotyping is a sensitive and cost effective method that not only detects cryptic subtelomeric rearrangements but also provides a unique opportunity to detect uniparental disomies. We suggest giving consideration to systematic examination of subtelomeric regions in the diagnostic work up of patients with unexplained syndromic mental retardation.
Service facilities for persons with severe mental retardation and multiple disabilities are meagre. The present study aims at analysing the problems of persons with severe mental retardation and multiple disabilities in terms of presenting complaints, previous consultations, aetiological factors and associated problems. Persons with severe mental retardation and multiple disabilities numbering 164 who sought services at NIMH over a period of 15 months were studied. They formed 22% of the total number of mentally retarded individuals registered during the period. The major presenting complaints were in the areas of sell help, language, epilepsy, motor problems and behaviour problems. Infection in Drain, birth anoxia and trauma were major aetiological categories in addition to a large number forming unknown category. Suitable service delivery models are suggested lot this population.
Background & objectives:
The aetiology of mental retardation is varied and difficult to establish. Reports from India on the spectrum of underlying causative conditions are lacking. This retrospective study was conducted to establish the various aetiologies of mental retardation (MR) and developmental delay (DD) in patients attending a medical genetics centre in north India and to assess the contribution of genetic disorders.
This retrospective study was conducted at a tertiary care centre in north India. All patients attending the centre with MR or DD from January 2007 to December 2009 were included. The aetiology of MR/DD was ascertained after clinical assessment and targeted laboratory evaluation. The spectrum of causative conditions and contribution of genetic disorders was established.
A total of 338 patients were included in the study, of whom definite diagnosis was established in 253 (74.8%). The various aetiological categories were: chromosomal disorders in 112 (33.1%), non chromosomal syndromes in 32 (9.5%), neurometabolic disorders in 34 (10.1%), central nervous system structural defects in 25 (7.4%), cerebral palsy in 43 (12.7%) and environmental insults in 7 (2%). Eighty five patients (25.2%) had idiopathic mental retardation. A total of 196 (58%) patients had a genetic disorder as the cause of MR/DD.
Interpretation & conclusions:
The aetiology of MR/DD is varied and difficult to establish in a significant proportion of patients. Chromosomal and various monogenic disorders contribute to a large number of MR/DD cases and hence a genetic work up is essential for all such patients.
Aetiology; developmental delay; genetic diseases; India; mental retardation
298 institutionalised mentally retarded patients in Institute of Mental Health, Madras were studied for the aetiological factors, levels of intelligence, associated disorders and family structure and compared with 163 matched group of mentally retarded attending the outpatient services of the Institute of Mental Health. In 41% of the institutionalised the cause was unknown, 29.3% had infective aetiology, 18% formed the primary group and 6.4% were due to genetic and chromosomal factors. Statistically significant number of institutionalised were severely subnormal, had more associated disorders and poor family structure. The need for the development of exclusive residential services for the mentally retarded and community oriented approach are discussed.
Most of the autistic disorder patients are also mentally retarded and many mentally retarded persons exhibit autistic symptoms. By using a standard instrument (Ritvo-Freeman Real Life Rating Scale) the autistic features of the mentally retarded children were studied. The study also examined the influence of age, sex and level of mental retardation on the occurrence of autistic symptoms. Children who came for consultation to child psychiatric unit were compared with those at a school for children with mental retardation receiving stimulation. Male children from child psychiatric unit had significantly higher scores than those from the school. Social and language impairment could be reliably identified and grouped. It was possible to diagnose the syndrome of autism in children with mental retardation in a significant number (9.6%)as compared to that was possible only clinically (1.9%). More number of children with severe/ profound mental retardation could be diagnosed as autistic. The autistic syndrome in children with mental retardation can be picked up more effectively by the use of structured instrument.
Autism; mental retardation
Ocular problems are common in mentally retarded children. Due to population growth these problems are increasing. Prevalence rate is variable from region to region. Data on ocular problems in mentally retarded school children is lacking in this region.
The aim of the present study was to identify the ocular disorders in children with mental retardation attending special schools in a district and to study their relationship with the degree of retardation.
Materials and Methods:
A total of 241 mentally retarded school children in the age group of 6-16 years attending special schools for the mentally retarded children in a district in central India were examined by a team of ophthalmologist, psychiatrist, and a resident in ophthalmology department of a medical college. Complete ocular examination was done. Ocular problems were identified and categorized according to the intelligent quotient.
One hundred and twenty four children (51.45%) had ocular problems. Strabismus (10.37%) and refractive error (20.75%) were the common ocular problems seen in this study. An association was found between the severity of mental retardation and ocular problems (P<0.005). However, no association was seen between the severity of mental retardation and strabismus and refractive error.
A high prevalence of ocular problems was seen in mentally retarded school children. Children with mental retardation should undergo annual ophthalmological check up. Early detection and correction of ocular problems will prevent visual impairment in future.
Children; mental retardation; ocular disorder; refractive error; strabismus
To determine the Prevalence of mental retardation in children 3 to 10 years of age.
Materials and Methods:
The study was conducted in the framework of a population based, single centre, cross-sectional study at R.S.Pura town, 22 kms south- west of Jammu city.
A total of 61 (0.79 percent) of the 7,707 children surveyed had positive screening results on the Ten Questions instrument. 56 (0.72percent) children were diagnosed as suffering from mental retardation. Serious mental retardation was diagnosed in 48 children and mild mental retardation was diagnosed in 8 children. The combined prevalence estimates of mild and serious mental retardation were 7.2/1000. No notable sex differences were observed for either serious or mild retardation.
The prevalence rates of mental retardation among children less than 19 years of age in R. S. town compares favorably with studies from developed world.
Children; mental retardation; prevalence
Mental and behavioral disorders among adults with Usher syndrome have been discussed and reported in some case studies but no research has been reported on children with Usher syndrome.
This article investigates the prevalence and characteristics of mental and behavioral disorders among 26 children, 3-17 years of age, with Usher syndrome.
Six of the 26 children were diagnosed with a mental or behavioral disorder (1 with schizophrenia and mild mental retardation, 1 with atypical autism and severe mental retardation, 1 with atypical autism and mild mental retardation, 1 with mild mental retardation, and 2 with conduct disorder). Another 3 children had had a mental or behavioral disorder previously in their childhood.
Even though vision impairment first manifests in late childhood, some children with Usher syndrome seem to develop mental and behavioral disorders during childhood. The aetiology and treatment of mental and behavioral disorders among children with Usher syndrome are discussed. Children with Usher syndrome and their parents may need clinical support during early childhood to prevent development of mental and behavioral disorders.
Deafblindness; Dual sensory loss; Mental and behavioral disorders; Usher syndrome; Psychiatry
Mental Retardation (MR) is a problem encountered in almost all paediatric clinical settings. The assessment of a child with MR is a common diagnostic and management dilemma for paediatricians. The field of MR research is currently in a state of flux regarding not just our understanding of the condition, but also in the language and the processes we use in naming, defining and describing MR. This article will provide a better understanding and a rational approach toward MR. Prevalence rates for MR are variable in the literature and may be attributable to the variation in major classification systems and the diversity in study operation definitions and methodologies. Etiologies of MR are diverse and include many different influences. MR most often presents during infancy or preschool years as developmental delay. There is no universally accepted approach to the etiological work-up of mental retardation. The number of medical conditions associated with MR that are completely treatable by medical means remains small. The paediatrician plays a key role establishing short and long term treatment goals, as well as providing support to families who have children with MR.
Children; Developmental delay; Mental retardation
There may be need to assess intelligent quotient (IQ) scores in sub-Saharan African children with intellectual disability, either for the purpose of educational needs assessment or research. However, modern intelligence scales developed in the western parts of the world suffer limitation of widespread use because of the influence of socio-cultural variations across the world. This study examined the agreement between IQ scores estimation among Nigerian children with intellectual disability using clinicians' judgment based on International Classification of Diseases, tenth Edition
(ICD - 10) criteria for mental retardation and caregivers judgment based on 'ratio IQ' scores calculated from estimated mental age in the context of socio-cultural milieu of the children. It proposed a viable option of IQ score assessment among sub-Saharan African children with intellectual disability, using a ratio of culture-specific estimated mental age and chronological age of the child in the absence of standardized alternatives, borne out of great diversity in socio-cultural context of sub-Saharan Africa.
Clinicians and care-givers independently assessed the children in relation to their socio-cultural background. Clinicians assessed the IQ scores of the children based on the ICD - 10 diagnostic criteria for mental retardation. 'Ratio IQ' scores were calculated from the ratio of estimated mental age and chronological age of each child. The IQ scores as assessed by the clinicians were then compared with the 'ratio IQ' scores using correlation statistics.
A total of forty-four (44) children with intellectual disability were assessed. There was a significant correlation between clinicians' assessed IQ scores and the 'ratio IQ' scores employing zero order correlation without controlling for the chronological age of the children (r = 0.47, df = 42, p = 0.001). First order correlation controlling for the chronological age of the children showed higher correlation score between clinicians' assessed IQ scores and 'ratio IQ' scores (r = 0.75, df = 41, p = 0.000).
Agreement between clinicians' assessed IQ scores and 'ratio IQ' scores was good. 'Ratio IQ' test would provide a viable option of assessing IQ scores in sub-Saharan African children with intellectual disability in the absence of culture-appropriate standardized intelligence scales, which is often the case because of great diversity in socio-cultural structures of sub-Saharan Africa.
Studies comparing the stress perceived by parents of mentally retarded and normal children are limited.
(i) To find whether there exists a difference in the perceived stress between both the parents of mentally retarded children, (ii) to study whether these stresses occur more frequently in parents of mentally retarded children compared with those of normal children, and (iii) to find any correlation between the severity of perceived stressors and the anxiety state of these parents.
This study was conducted in the Child Guidance Clinic of a tertiary care psychiatry hospital. The study sample, comprising 180 subjects, was categorized as: group A (60 parents of profound to moderately mentally retarded children), group B (60 parents of mild to borderline mentally retarded children) and group C (60 parents of children with normal intelligence), which served as the control group. Each parent was evaluated using the Family Interview for Stress and Coping (FISC) in Mental Retardation, and the Hamilton Anxiety Rating Scale (HARS).
Parents in group A had a significantly higher frequency of stressors and level of anxiety as compared to those in groups B and C. A positive correlation was found between the level of anxiety and stressors.
Multifaceted factors made parents in groups A and B more vulnerable to stress compared with parents in the control group.
Mental retardation; anxiety; stressors
Risk factors for mental retardation were studied prospectively in 12 000 children born in northern Finland in 1966 and followed to the age of 14 years. The number of untraced children was less than 2 per 1000. Altogether 326 children had an IQ less than 86, and the incidence of severe retardation (IQ less than 50) was especially high. An incidence figure for children with mental retardation, a separate figure for healthy children, and also the death rate were calculated for each disease. Only in the cases of Down's syndrome and some hereditary diseases were all the exposed children mentally retarded; in other diseases some children did not seem to suffer any sequelae. A risk factor could be found for 50.6% of the total number of children with mental retardation, the percentage decreasing from the severest to the mildest form (86.7%, 45.4%, and 30.9%). Some 9.4% of the healthy children and 77.7% of those who died had had one or more of these conditions. Prenatal conditions were most often associated with severe mental retardation (64%), and perinatal conditions with mild retardation, (IQ 50 to 70; 27%) and mental subnormality (IQ 71 to 85; 18%). Cases with no known risk factor were more common among boys than girls.
The study was carried out with the aim of determining the factors affecting and to evaluate anxiety situations and self-esteem of children with and without mentally retarded siblings.
Materials and Methods:
The sampling included 227 healthy children: 108 of them have mental retarded sibling and 119 of them do not have mental retarded sibling. The context of this study consisted of 15-18 year of age healthy children with mentally retarded siblings and 15-18 year of aged healthy children having at least one sibling between the dates February 15st and June 26st 2010. Personal Information Form, Rosenberg Self-Esteem Scale and Trait Anxiety Scale were used.
It was found out that trait anxiety of 17-18 aged of children with mental retarded sibling (47.04 ± 7.3) was higher than that of the children without mental retarded siblings (44.05 ± 11.23) (P < 0.05). It was observed that self-esteem of children with mentally retarded sibling was not affected from the handicap of their siblings (P > 0.05). Trait anxiety score averages of children with mentally retarded sibling and experience some difficulties due to his or her siblings's handicap (47.00 ± 7.76) were found higher than those of those of the children without any problem with the environment (42.61 ± 7.48) (P < 0.05).
Although the average score of trait anxiety and self-esteem in both groups were not significant different, score of trait anxiety for children with mentally disabled siblings was higher in comparison. It was concluded that anxiety of children with and without mentally retarded siblings increased as self-esteem of these children decreased.
Mental retardation; self-esteem; sibling; trait anxiety
Microdeletions within chromosome 15q13.3 are associated both with a recently recognised syndrome of mental retardation, seizures, and dysmorphic features, and with schizophrenia.
Methods and results
Based on routine diagnostic testing of ~8200 samples using array comparative genomic hybridisation, we identified 20 individuals (14 children and six parents in 12 families) with microdeletions of 15q13.3. Phenotypes in the children included developmental delay, mental retardation, or borderline IQ in most and autistic spectrum disorder (6/14), speech delay, aggressiveness, attention deficit hyperactivity disorder, and other behavioural problems. Both parents were available in seven families, and the deletion was de novo in one, inherited from an apparently normal parent in four, and inherited from a parent with learning disability and bipolar disorder in two families. Of the 14 children, six in five families were adopted, and DNA was available for only one of these 10 biological parents; the deletion was very likely inherited for one of these families with two affected children. Among the unavailable parents, two mothers were described as having mental retardation, another mother as having “mental illness”, and one father as having schizophrenia. We hypothesise that some of the unavailable parents have the deletion.
The occurrence of increased adoption, frequent autism, bipolar disorder, and lack of penetrance are noteworthy findings in individuals with deletion 15q13.3. A high rate of adoption may be related to the presence of the deletion in biological parents.
Unconfirmed histories of antisocial behaviours in unavailable biological parents raise the concern that future research may show that deletion 15q13.3 is associated with such behaviours.
The aim of this study was to evaluate anxiety, depression, alexithymia, and general psychological symptoms in the mothers of autistic children in comparison with those in the mothers of mentally retarded children. Forty mothers of autistic children and 38 mothers of mentally retarded children were included in the study. After a clinical interview, psychometric tests were performed for depression, anxiety, alexithymia, and Symptom Distress Check List (SCL-90) for general psychological symptoms. Non-depression rates was 27.5% in the mothers of autistic children whereas the rate was 55.3% in the mothers of mentally retarded children. There was no difference regarding anxiety and alexithymia between the two groups. The psychopathology in the mothers of autistic children was more frequent than in those of mentally retarded children in all sub-scales of SCL-90 (somatization obsessive-compulsive, interpersonal sensitivity, depression, anxiety, anger-hostility, phobic anxiety, paranoid thought, psychotism, and extra scale). The mothers of autistic children experienced more psychological distress than those of mentally retarded children. Our findings indicates that the assessment of autistic and mentally retarded children should include psychological assessment of their mothers.
Objective: The frequency of subtelomeric rearrangements in patients with unexplained mental retardation (MR) is uncertain, as most studies have been retrospective and case retrieval may have been biased towards cases more likely to have a chromosome anomaly. To ascertain the frequency of cytogenetic anomalies, including subtelomeric rearrangements, we prospectively screened a consecutive cohort of cases with unexplained MR in an academic tertiary centre.
Methods: Inclusion criteria were: age <18 years at referral, IQ<85, no aetiological diagnosis after complete examination, which included karyotyping with high resolution banding (HRB).
Results: In 266 karyotyped children, anomalies were detected in 20 (7.5%, seven numerical, 13 structural); 39 cases were analysed by FISH for specific interstitial microdeletions, and anomalies were found in nine (23%). FISH analyses for subtelomeric microdeletions were performed in 184 children (44% moderate-profound MR, 51% familial MR), and one rearrangement (0.5%) was identified in a non-familial MR female with mild MR (de novo deletion 12q24.33-qter). The number of probable polymorphisms was considerable: 2qter (n=7), Xpter (n=3), and Ypter (n=1). A significantly higher total number of malformations and minor anomalies was present in the cytogenetic anomaly group compared to the group without cytogenetic anomalies.
Conclusions: The total frequency of cytogenetic anomalies in this prospective study was high (1:10), but the frequency of subtelomeric rearrangements was low. The most likely explanations are the high quality of HRB cytogenetic studies and the lack of clinical selection bias. Conventional cytogenetic analyses, combined with targeted microdeletion testing, remain the single most effective way of additional investigation in mentally retarded children, also in a tertiary centre.