doublecortin is the major gene causing X-linked subcortical laminar heterotopia (SCLH).
Subcortical laminar heterotopia (SCLH), or 'double cortex', is a cortical dysgenesis disorder associated with a defect in neuronal migration. Clinical manifestations are epilepsy and mental retardation. This disorder, which mainly affects females, can be inherited in a single pedigree with lissencephaly, a more severe disease which affects the male individuals. This clinical entity has been described as X-SCLH/LIS syndrome. Recently we have demonstrated that the doublecortin gene, which is localized on the X chromosome, is implicated in this disorder. We have now performed a systematic mutation analysis of doublecortin in 11 unrelated females with SCLH (one familial and 10 sporadic cases) and have identified mutations in 10/11 cases. The sequence differences include nonsense, splice site and missense mutations and these were found throughout the gene. These results provide strong evidence that loss of function of doublecortin is the major cause of SCLH. The absence of phenotype-genotype correlations suggests that X-inactivation patterns of neuronal precursor cells are likely to contribute to the variable clinical severity of this disorder in females.
des Portes
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V
INSERM U129, Institut Cochin de Génétique Moléculaire, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France.
Francis
F
F
Pinard
J M
JM
Desguerre
I
I
Moutard
M L
ML
Snoeck
I
I
Meiners
L C
LC
Capron
F
F
Cusmai
R
R
Ricci
S
S
Motte
J
J
Echenne
B
B
Ponsot
G
G
Dulac
O
O
Chelly
J
J
Beldjord
C
C
D000015:Abnormalities, Multiple / Q000235:genetics; D002540:Cerebral Cortex / Q000002:abnormalities; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D000089622:Doublecortin Domain Proteins; D004827:Epilepsy / Q000235:genetics*; D005260:Female; D005796:Genes; D008040:Genetic Linkage; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D008869:Microtubule-Associated Proteins; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics*; D010375:Pedigree; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014960:X Chromosome
D000089622:Doublecortin Domain Proteins; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides