Deletion of 9p associated with gonadal dysfunction in 46,XY but not in 46,XX human fetuses

A locus on distal 9p has been reported to be deleted in patients with mental retardation, craniofacial dysmorphic traits, notably trigonocephaly, and a high frequency of genital and/or gonadal anomalies (Alfi's syndrome).1 More recently, some cases of 46,XY male to female sex reversal without dysmorphic traits have been described in association with distal deletions of 9p.2–5 46,XY patients described so far have had gonadal anomalies ranging from streak gonads, to partially masculinised dysgenetic gonads, to normal testes. A family of genes containing a unique zinc finger DNA binding domain, which has been called DM, as it is contained in two proteins involved in invertebrate sex determination, doublesex and mab-3, has recently been recognised. Three genes belonging to this family have been identified on 9p24.3, immediately proximal to the centromeric boundary of the minimal region, which is required in two copies for testis development.5 The first gene identified was termed DMRT1 and the two additional DM gene family members are placed in tandem more distally to the breakpoint of the minimal deleted region.6,7 DMRT1 is transcribed only in the embryonic gonads of both sexes and in fetal and adult testis, and is required for postnatal differentiation of both somatic and germ cells in the mouse testis.8 Therefore, this gene is a good candidate to explain the 46,XY sex reversal associated with 9p deletions. Recently, a 1 year old 46,XX female patient with premature ovarian failure and deletion of 9p was reported.9 This led to the suggestion of a role for a gene located on 9p in both male and female gonadal development. DMRT1 represents a good candidate for a function in both sexes as it is expressed in the genital ridge in both sexes in mouse and humans.7,8 Here, we report …