BACKGROUND: Oligomeganephronia (OMN) is a rare congenital and usually sporadic anomaly. It is characterized by bilateral renal hypoplasia, with a reduced number of enlarged nephrons. The mechanisms involved in this deficient nephrogenesis are unknown. The paired box transcription factor PAX2 plays a fundamental role in renal development. Heterozygous Pax2 mutants in mice are characterized by renal hypoplasia and retinal defects, and in humans, PAX2 mutations have been described in the renal-coloboma syndrome. METHODS: To assess whether OMN could be related to PAX2, we searched for PAX2 mutations in nine patients presenting with sporadic and apparently isolated OMN. RESULTS: Heterozygous PAX2 mutations were found in three patients. A limited optic nerve coloboma was secondarily detected in two cases and a very mild optic disk dysplasia in one patient. None of these patients had visual impairment. CONCLUSIONS: Ocular anomaly and PAX2 mutations should be sought in all patients with OMN.
BACKGROUND: Oligomeganephronia (OMN) is a rare congenital and usually sporadic anomaly. It is characterized by bilateral renal hypoplasia, with a reduced number of enlarged nephrons. The mechanisms involved in this deficient nephrogenesis are unknown. The paired box transcription factor PAX2 plays a fundamental role in renal development. Heterozygous Pax2 mutants in mice are characterized by renal hypoplasia and retinal defects, and in humans, PAX2 mutations have been described in the renal-coloboma syndrome. METHODS: To assess whether OMN could be related to PAX2, we searched for PAX2 mutations in nine patients presenting with sporadic and apparently isolated OMN. RESULTS: Heterozygous PAX2 mutations were found in three patients. A limited optic nerve coloboma was secondarily detected in two cases and a very mild optic disk dysplasia in one patient. None of these patients had visual impairment. CONCLUSIONS:Ocular anomaly and PAX2 mutations should be sought in all patients with OMN.