Isolated congenital renal tubular immaturity in siblings

This paper describes two cases of an unusual renal abnormality discovered in anuric siblings (one male, one female) who were born at 36 and 34 weeks of gestation and died of systemic complications secondary to severe pulmonary hypoplasia shortly after birth. Both gestations were complicated by marked oligohydramnios. Antenatal ultrasound examinations showed slightly enlarged kidneys in the first case and normal kidneys in the second case, with no evidence of hydronephrosis or cystic disease in either. With the exception of enlargement of the first infant's kidneys, autopsies revealed grossly unremarkable kidneys and ureters. Microscopy, however, demonstrated increased glomerulogenesis with normal glomeruli and global immaturity of renal tubules and ducts without concomitant features of dysplasia. Immunoperoxidase staining for epithelial membrane antigen revealed the immaturity or complete absence of proximal convoluted tubules. This precise constellation of findings had not been described previously. One other similar family has been documented in a report implicating genetic factors. In the present cases, the possibility of a cocaine-associated etiology is also addressed.