ARPKD is a common heritable cystic renal disease with an estimated incidence of 1 in 6000 to 50 000 live births.1 2
The diagnosis of ARPKD is based on characteristic histopathological findings of the kidney and liver; the kidneys are grossly enlarged with multiple cysts on the external surface that involve the cortex and medulla and are located in collecting ducts and tubules, lined by cuboidal epithelium; grossly, cysts are also present in an enlarged liver where they form due to enlarged portal areas forming anastomosing channels, with the biliary structures forming dilated sacs.5
Hepatic fibrosis is an essential diagnostic criterion for this autosomal recessive disease.6
The involvement of the renal collecting system and hepatic ductal plate malformation is due to failure of terminal differentiation of the collecting duct and biliary systems, causing oligohydramnios leading to pulmonary hypoplasia which is the cause of morbidity, in 30% of cases.3 7
Similar histopathological findings were evident on autopsy in our case.
Prenatal diagnosis using fetal sonography can be unreliable, especially in early pregnancy; however, serial ultrasound evaluation for hyperechogenicity resulting from presence of multiple microcysts, dysplasia or tubular dilatation starting at 15 weeks can be used, as a screening modality.4
Serial ultrasonographic evaluation in this pregnancy showed decreasing amniotic fluid level and enlargement of kidneys as the pregnancy progressed.
The genetic abnormality linked to ARPKD is limited to chromosome 6p21.1-p12, is a single gene disorder (PKHD1 gene) and is due to protein polyductin also known as fibrocystin.8
Haplotype based prenatal testing in pregnancies 'at risk' for ARPKD has been proposed, albeit with absolute prerequisite of confirmed diagnosis of the disorder in previously affected sibling(s).2
We conclude that an autopsy with histopathological examination must be performed in cases of infant death for a confirmatory diagnosis of ARPKD where prenatal ultrasonographic findings and clinical history are suggestive of the disease.
- The diagnosis of autosomal recessive polycystic kidney disease (ARPKD) is based on characteristic histopathological findings of kidneys and liver.
- Serial ultrasonographic examinations are a useful prenatal screening modality for ARPKD.
- In cases of first pregnancy associated with neonatal death where antenatal ultrasonographic findings are suggestive of ARPKD, an autopsy with emphasis on histopathological examination of the kidneys and liver must be performed to confirm or negate ARPKD.
- Chromosomal analysis of the parents and evaluation for polyductin/fibrocystin protein in affected fetuses are important diagnostic tools.
- To prevent future loss of pregnancy, the parents should be given genetic counselling in all such cases.