A gene involved in XY sex reversal is located on chromosome 9, distal to marker D9S1779.
The genetic mechanisms involved in sex differentiation are poorly understood, and progress in identification of the genes involved has been slow. The fortuitous finding of chromosomal rearrangements in association with a sex-reversed phenotype has led to the isolation of SRY and SOX9, both shown to be involved in the sex-determining pathway. In addition, duplications of the X chromosome, deletions of chromosomes 9 and 10, and translocations involving chromosome 17 have been reported to be associated with abnormal testicular differentiation, leading to male-to-female sex reversal in 46,XY individuals. We present the cytogenetic and molecular analyses of four sex-reversed XY females, each with gonadal dysgenesis and other variable malformations, and with terminal deletions of distal chromosome 9p, resulting from unbalanced autosomal translocations. PCR amplification and DNA sequence analysis of SRY revealed no mutations in the high-mobility-group domain (i.e., HMG box) in any of the four patients. Conventional and molecular cytogenetic analyses of metaphase chromosomes from each patient suggest that the smallest region of overlap (SRO) of deletions involves a very small region of distal band 9p24. Loss-of-heterozygosity studies using 17 highly polymorphic microsatellite markers, as well as FISH using YAC clones corresponding to the most distal markers on 9p, showed that the SRO lies distal to marker D9S1779. These results significantly narrow the putative sex-determining gene to the very terminal region of the short arm of chromosome 9.
Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA. wflejter@wfubmc.edu
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Flejter
J
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Fergestad
J
J
Gorski
T
T
Varvill
S
S
Chandrasekharappa
D002675:Child, Preschool; D002874:Chromosome Mapping; D002899:Chromosomes, Human, Pair 9; D004268:DNA-Binding Proteins / Q000235:genetics; D012734:Disorders of Sex Development; D005260:Female; D005819:Genetic Markers; D006609:High Mobility Group Proteins / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D008297:Male; D018895:Microsatellite Repeats; D005810:Multigene Family; D009687:Nuclear Proteins; D010375:Pedigree; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D055758:SOX9 Transcription Factor; D019849:Sex Determination Processes; D012733:Sex Differentiation; D051876:Sex-Determining Region Y Protein; D013737:Testis / Q000196:embryology; D014157:Transcription Factors / Q000235:genetics; D014960:X Chromosome; D014998:Y Chromosome
D004268:DNA-Binding Proteins; D005819:Genetic Markers; D006609:High Mobility Group Proteins; D009687:Nuclear Proteins; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; C497745:SRY protein, human; D051876:Sex-Determining Region Y Protein; D014157:Transcription Factors