Familial case with sequence variant in the testis-determining region associated with two sex phenotypes

The human Y chromosome encodes a testis-determining factor (TDF) which is responsible for initiating male sex determination. Recently a region of the Y chromosome (SRY) was identified as part of the TDF gene. We have identified a three-generation family (N) in which all XY individuals have a single base-pair substitution resulting in a conservative amino acid change in the conserved domain of the SRY open reading frame. Three individuals are XY sex-reversed females, and two are XY males. Several models are proposed to explain association between a sequence variant in SRY and two sex phenotypes.