No significant linkage was found to 6p, where a renal and ureteric malformation locus has been reported, or to PAX2, mutations of which cause VUR in renal-coloboma syndrome.
Although renal-coloboma syndrome involves both ocular and renal anomalies, some patients are affected with vesico-ureteral reflux (VUR), high frequency hearing loss, central nervous system (CNS) anomalies, and/or genital anomalies, consistent with the expression of PAX2 in these tissues during development.
In addition, a polymorphic dinucleotide repeat marker located within the PAX2 gene segregated independently of the disease trait in one large family who primarily had VUR or reflux nephropathy.