Analysis of X chromosome inactivation in autism spectrum disorders.
Autism spectrum disorders (ASD) are complex genetic disorders more frequently observed in males. Skewed X chromosome inactivation (XCI) is observed in heterozygous females carrying gene mutations involved in several X-linked syndromes. In this study, we aimed to estimate the role of X-linked genes in ASD susceptibility by ascertaining the XCI pattern in a sample of 543 informative mothers of children with ASD and in a sample of 163 affected girls. The XCI pattern was also determined in two control groups (144 adult females and 40 young females) with a similar age distribution to the mothers sample and affected girls sample, respectively. We observed no significant excess of skewed XCI in families with ASD. Interestingly, two mothers and one girl carrying known mutations in X-linked genes (NLGN3, ATRX, MECP2) showed highly skewed XCI, suggesting that ascertainment of XCI could reveal families with X-linked mutations. Linkage analysis was carried out in the subgroup of multiplex families with skewed XCI (> or = 80:20) and a modest increased allele sharing was obtained in the Xq27-Xq28 region, with a peak Z-score of 1.75 close to rs719489. In summary, our results suggest that there is no major X-linked gene subject to XCI and expressed in blood cells conferring susceptibility to ASD. However, the possibility that rare mutations in X-linked genes could contribute to ASD cannot be excluded. We propose that the XCI profile could be a useful criteria to prioritize families for mutation screening of X-linked candidate genes.
Gong
Xiaohong
X
Human Genetics and Cognitive Functions, Institut Pasteur, Paris, France.
Bacchelli
Elena
E
Blasi
Francesca
F
Toma
Claudio
C
Betancur
Catalina
C
Chaste
Pauline
P
Delorme
Richard
R
Durand
Christelle M
CM
Fauchereau
Fabien
F
Botros
Hany Goubran
HG
Leboyer
Marion
M
Mouren-Simeoni
Marie-Christine
MC
Nygren
Gudrun
G
Anckarsäter
Henrik
H
Rastam
Maria
M
Gillberg
I Carina
IC
Gillberg
Christopher
C
Moreno-De-Luca
Daniel
D
Carone
Simona
S
Nummela
Ilona
I
Rossi
Mari
M
Battaglia
Agatino
A
Jarvela
Irma
I
Maestrini
Elena
E
Bourgeron
Thomas
T
D000293:Adolescent; D000328:Adult; D001321:Autistic Disorder / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D041321:Chromosomes, Human, X / Q000235:genetics; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D009035:Mothers; D049951:X Chromosome Inactivation / Q000502:physiology*