Loss of ZDHHC15 expression in a woman with a balanced translocation t(X;15)(q13.3;cen) and severe mental retardation.
X-linked mental retardation (XLMR) affects one in 600 males and is highly heterogeneous. We describe here a 29-year-old woman with severe nonsyndromic mental retardation and a balanced reciprocal translocation between chromosomes X and 15 [46,XX,t(X;15)(q13.3;cen)]. Methylation studies showed a 100% skewed X-inactivation in patient-derived lymphocytes indicating that the normal chromosome X is retained inactive. Physical mapping of the breakpoints localised the Xq13.3 breakpoint to within 3.9 kb of the first exon of the ZDHHC15 gene encoding a zinc-finger and a DHHC domain containing product. Expression analysis revealed that different transcript variants of the gene are expressed in brain. ZDHHC15-specific RT-PCR analysis on lymphocytes from the patient revealed an absence of ZDHHC15 transcript variants, detected in control samples. We suggest that the absence of the ZDHHC15 transcripts in this patient contributes to her phenotype, and that the gene is a strong candidate for nonsyndromic XLMR.
Mansouri
Mahmoud Reza
MR
Department of Genetics and Pathology, Uppsala University, Sweden.
Marklund
Lena
L
Gustavsson
Peter
P
Davey
Edward
E
Carlsson
Birgit
B
Larsson
Catharina
C
White
Irene
I
Gustavson
Karl-Henrik
KH
Dahl
Niklas
N
D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D002884:Chromosomes, Human, Pair 15; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D038901:X-Linked Intellectual Disability / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D014178:Translocation, Genetic; D049951:X Chromosome Inactivation
D004268:DNA-Binding Proteins; C505905:ZDHHC15 protein, human