Renal anomalies in families of individuals with congenital solitary kidney.
OBJECTIVE
Congenital solitary kidney affects 1 in 1000 persons, whereas bilateral renal agenesis affects 1 in 5000. Because congenital solitary kidney is increased in parents of infants with bilateral renal agenesis and fetuses with renal anomalies on ultrasound, offspring of patients with congenital solitary kidney may be at risk of both unilateral and bilateral renal anomalies. The goal was to establish empiric risk estimates for counseling individuals with congenital solitary kidney.


METHODS
Through a computerized review of records, subjects with congenital solitary kidney (defined as presumably congenital absence or severely reduced function of one kidney) were identified and asked to complete a questionnaire regarding urogenital anomalies in relatives.


RESULTS
Empiric risks of 7% for offspring, 4% for parents, and 2.5% for siblings are minimal because not all relatives underwent ultrasound studies. The incidence of bilateral renal agenesis in offspring of congenital solitary kidney probands is 0.8%, which is much greater than the population risk but less than that for families with previous bilateral renal agenesis. Concordance for type of anomaly in affected relatives is only 50%, suggesting that various anomalies included in congenital solitary kidney (agenesis, dysplasia, cystic dysplasia) may overlap. Horseshoe kidney has 80% concordance and may be a separate autosomal dominant condition.


CONCLUSIONS
Offspring and other relatives of individuals with congenital solitary kidney have significantly increased renal disease. Ultrasound is recommended for first-degree relatives, including fetuses at risk.
McPherson
Elizabeth
E
Department of Medical Genetic Services, Marshfield Clinic, Marshfield, Wisconsin 54449, USA. mcpherson.elizabeth@marshfieldclinic.org
D015331:Cohort Studies; D005190:Family; D005260:Female; D005817:Genetic Counseling; D006801:Humans; D007668:Kidney / Q000002:abnormalities* / Q000000981:diagnostic imaging; D007674:Kidney Diseases / Q000151:congenital* / Q000453:epidemiology; D008297:Male; D018570:Risk Assessment; D011795:Surveys and Questionnaires; D014463:Ultrasonography; D014564:Urogenital Abnormalities / Q000453:epidemiology / Q000235:genetics*; D014922:Wisconsin / Q000453:epidemiology