DELETION OF THE DM-DOMAIN GENE CLUSTER IN A FETUS WITH RING CHROMOSOME 9 AND SEX REVERSAL

Deletions of the distal short arm of chromosome 9 have been reported in association with gonadal dysgenesis and XY sex reversal. These findings suggest that this region harbors at least one gene that might be involved in sexual development. Recent studies narrowed the deletion interval to the subtelomeric region 9p24.3. This region contains three genes DMRT1, DMRT3, and DMRT2 characterized by a DM-domain that seems essential for sexual development in Nematoda and Arthropoda. We have investigated the possible role of this gene cluster in a fetus with ring chromosome 9 and male-to-female sex reversal. We could demonstrate by FISH analysis a very small deletion of the terminal short arm of chromosome 9 including the DM-domain gene cluster. This finding gives further evidence that hemizygosity of this region can be the cause for male-to-female sex reversal.