The SH3BGR gene has been recently isolated and mapped to chromosome 21 with
in the Down syndrome (DS) congenital heart disease (CHD) minimal region. As
a first step to evaluate the possible involvement of SH3BGR in CHD that af
fect 40% of DS patients, we have analyzed by in situ hybridization the expr
ession pattern of the mouse homolog gene (Sh3bgr), during development. Our
results show that Sh3bgr is already expressed at embryonic day 7.75 (E7.75)
in the precardiogenic mesoderm and that from E8.5 to E10.5 its expression
is restricted to the heart. In subsequent developmental stages, Sh3bgr tran
scripts are also detected in skeletal muscle and in some visceral smooth mu
scles including urinary bladder and gut wall, but not in vascular smooth mu
scle. Our results, demonstrating that Sh3bgr is expressed in earliest stage
s of mouse heart development, support a possible role of this gene in heart
morphogenesis and, consequently, in the pathogenesis of CHD in DS. (C) 200
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