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The schematic of a family tree shows the facial appearance of three women (fig 11).). The woman in panel A is in her mid 50s and her two daughters (panels B and C) are both in their 30s. All three women are well and in full time employment. On examination the woman shown in panel A has a soft systolic murmur in the pulmonary area. She has a past history of heart valve surgery performed at the age of 19 years and correction of unilateral ptosis as a child. The woman shown in panel B also has a soft systolic murmur at the upper left sternal edge. She has a daughter (D) who is well and of normal phenotype. The woman in panel C has a normal cardiovascular examination. All three women are just under 5 feet (1.5 m) in height.
Turner syndrome occurs exclusively in females and is differentiated from Noonan syndrome by demonstration of a sex chromosome abnormality. It is not a possible differential in the women we describe, as Turner syndrome results in infertility. The phenotype in Turner syndrome is actually quite different. Left sided cardiac abnormalities are the rule, and renal abnormalities and developmental delay are more common.
Cardiofaciocutaneous syndrome occurs sporadically. It has similar cardiac findings to Noonan syndrome; however, developmental delay is severe with a higher likelihood of structural central nervous system abnormalities.
Leopard syndrome is an autosomal dominant syndrome characterised by multiple lentigines and café au lait spots, electrocardiographic conduction abnormalities, ocular hypertelorism/obstructive cardiomyopathy, abnormalities of the genitalia in males, retardation of growth, and deafness. Leopard syndrome shares many features with Noonan syndrome, in which lentignes and deafness are usually not present. Molecular studies have shown that Noonan syndrome and Leopard syndrome are caused by different mis‐sense mutations in the same PTPN11 gene.
It is clearly important to identify Noonan syndrome in order to allow evaluation of associated cardiac abnormalities. Interestingly, the signs and symptoms of Noonan syndrome lessen with age and most adults do not require specialist medical intervention.
Competing interests: None stated