A novel mutation in the putative DNA helicase XH2 is responsible for male-to-female sex reversal associated with an atypical form of the ATR-X syndrome.
We describe a pedigree presenting X-linked severe mental retardation associated with multiple congenital abnormalities and 46,XY gonadal dysgenesis, leading in one family member to female gender assignment. Female carriers are unaffected. The dysmorphic features are similar to those described in the alpha-thalassemia and mental retardation (ATR-X) syndrome, although there is no clinical evidence of alpha-thalassemia in this family. In addition, the family had other clinical features not previously observed in the ATR-X syndrome, including partial optic-nerve atrophy and partial ocular albinism. Mutations in a putative DNA helicase, termed XH2, have been reported to give rise to the ATR-X syndrome. We screened the XH2 gene for mutations in affected members of the family and identified a 4-bp deletion at an intron/exon boundary that removes an invariant 3' splice-acceptor site. The mutation cosegregates with the syndrome. The genomic deletion causes missplicing of the pre-mRNA, which results in the loss of 8 bp of coding sequence, thereby generating a frameshift and a downstream premature stop codon. Our finding increases the range of clinical features associated with mutations in the XH2 gene.
Ion
A
A
Laboratoire de Cytogénétique Constitutionnelle, Hôpital St. Vincent dePaul, Paris, France.
Telvi
L
L
Chaussain
J L
JL
Galacteros
F
F
Valayer
J
J
Fellous
M
M
McElreavey
K
K
D000015:Abnormalities, Multiple / Q000235:genetics*; D000293:Adolescent; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D004265:DNA Helicases / Q000235:genetics; D017931:DNA Primers; D012734:Disorders of Sex Development; D005091:Exons; D005260:Female; D005819:Genetic Markers; D006061:Gonadal Dysgenesis, 46,XY / Q000235:genetics*; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000235:genetics*; D007438:Introns; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012322:RNA Precursors / Q000378:metabolism; D017384:Sequence Deletion; D013577:Syndrome; D000075924:X-linked Nuclear Protein; D017085:alpha-Thalassemia / Q000235:genetics*
D017931:DNA Primers; D005819:Genetic Markers; D009687:Nuclear Proteins; D012322:RNA Precursors; D004265:DNA Helicases; C092332:ATRX protein, human; D000075924:X-linked Nuclear Protein