The 'skipped generation' phenomenon in a family with renal agenesis.

Renal agenesis may be unilateral or bilateral, isolated or associated with anomalies of the internal genitalia or other systems. Renal anomalies are often considered sporadic. Because of their variable expressivity, only a few cases of affected relatives have been reported. In 1934, Madisson first described affected sibs 1 ; since then more than 70 familial cases have been reported 2 – 15 . There are no consistent phenotypic differences between sporadic and familial renal agenesis. Even if pedigrees suggestive of autosomal-recessive 8 , multifactorial 9 , Xlinked and polygenic 10 inheritance have been reported, the majority appear consistent with an autosomal-dominant inheritance with incomplete penetrance (50–90%) and variable expressivity