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Abstract:
Dyslexia is a form of reading disability that affects a
significant proportion of children. Efforts to explain dyslexia
have identified neural and chromosomal risk factors for dyslexia
and the deficits related to dyslexia. The chromosomal markers
implicated in dyslexia include regions associated with a variety of
developmental abnormalities. A neural risk factor related to
dyslexia, Heschlis gyrus duplication (HGD), may be one aspect of
the phenotypic expression of genes within the chromosomal regions
linked to dyslexia. The goal of this study was to determine if HGD
is an inherited trait. We studied twenty-seven sets of siblings and
4 families (n=17) who had received a volumetric MRI. There was a
significant association among the siblings for left (r=.388,
p=.048) and right Heschlis morphology (r=.404, p=.041). The
morphology of Heschlis gyrus was frequently discordant in the two
hemispheres (r=-.138, ns), suggesting the development of the two
gyri is not tightly co-regulated. Among the families, a right HGD
exhibited a traditional Mendelian dominant pattern of inheritance.
There was not a clear pattern of inheritance for the left HGD.
These preliminary data provide support for the strategy of
identifying anatomical risk factors that may mediate complex
behavioral phenotypes. Supported by the March of Dimes & DCD
RO1 2922.
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