Hoxa-13 gene mutation results in abnormal seminal vesicle and prostate development

The role of Hoxa-13 in postnatal morphogenesis of the male accessory sex or gans was assessed by correlating the Hoxa-13 expression domain with phenoty pic abnormalities in heterozygous Hypodactyly mutants. Hypodactyly is a nat urally occurring semi-dominant mutation that results from a 50-base pair de letion in exon one of the Hoxa-13 allele. We demonstrate that Hoxa-13 is br oadly expressed in the developing lower genitourinary tract and that the Hy podactyly mutation results in a specific phenotype characterized by decreas ed size and branching of the dorsolateral and ventral prostate and abnormal seminal vesicle morphology. This phenotype partially overlaps the genitour inary phenotype observed in Hoxd-13 deficient mice and comparison showed si milar domains of Hoxa-13 and Hoxd-13 expression in the lower genitourinary tract. The similarity in expression and overlap in phenotype resulting from mutation is consistent with additive function and partial functional redun dancy of Hoxa-13 and Hoxd-13 in male accessory sex organ development.