13qsyndrome is known to have widely variable manifestation of brain and heart, anal atresia, and anomalies of face and limbs. Here we describe a case with penoscrotal inversion, hypospadias,  imperforate anus and a subtelomeric deletion of chromosome 13q. In addition, he had unilateral renal agenesis. We propose that these patients represent a clinically recognizable, novel chromosomal microdeletion syndrome. The findings indicate the presence of a major gene(s) on chromosome 13q22 that regulate(s) the migration and development of anorenogenital cells and organs. We speculate that mutations of this developmental gene(s) may also result in more frequent congenital malformations (isolated hypospadias, uterus bicornis, unilateral renal agenesis).

Keywords: Chromosome 13; Imperforate anus; Penoscrotal transposition.