Non-skewed X-inactivation may cause mental retardation in a female carrier of X-linked alpha-thalassemia/mental retardation syndrome (ATR-X): X-inactivation study of nine female carriers of ATR-X.
X-linked alpha-thalassemia/mental retardation syndrome (ATR-X) is a syndromic form of X-linked mental retardation. We investigated the X-inactivation status of nine female ATR-X carriers by methylation-specific PCR of the HUMARA gene. Six carriers demonstrated a skewed X-inactivation pattern (>90:10) and one showed a non-skewed pattern (72:28), while two were uninformative because of homozygosity for the CAG repeat polymorphic alleles in the HUMARA. Only the carrier mother who showed non-skewed X-inactivation had moderate mental retardation. These findings suggest that mutations in ATRX may cause mental retardation in females, if the X chromosome carrying mutated ATRX is not properly inactivated.
Wada
Takahito
T
Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto, Japan. twada@sch.md.shinshu-u.ac.jp
Sugie
Hideo
H
Fukushima
Yoshimitsu
Y
Saitoh
Shinji
S
D041321:Chromosomes, Human, X / Q000235:genetics*; D004265:DNA Helicases / Q000235:genetics*; D019175:DNA Methylation; D004303:Dosage Compensation, Genetic; D005260:Female; D008040:Genetic Linkage; D006579:Heterozygote; D006801:Humans; D038901:X-Linked Intellectual Disability / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D011944:Receptors, Androgen / Q000235:genetics; D000075924:X-linked Nuclear Protein; D017085:alpha-Thalassemia / Q000235:genetics*
C410798:AR protein, human; D009687:Nuclear Proteins; D011944:Receptors, Androgen; D004265:DNA Helicases; C092332:ATRX protein, human; D000075924:X-linked Nuclear Protein