Homozygosity mapping in a family with microcephaly, mental retardation, and short stature to a Cohen syndrome region on 8q21.3-8q22.1: redefining a clinical entity.

A syndrome of microcephaly, progressive postnatal growth deficiency, and mental retardation was observed in two brothers and their cousin from a multiply consanguineous kindred of Lebanese descent.
Hypotonia, chorioretinal dystrophy, and myopia were also identified.
The severity of the condition varied among the closely related patients.
Because of absence of a distinctive facial appearance, the degree of mental retardation, and short stature, the initially considered clinical diagnosis of Cohen syndrome was withdrawn and a novel genetic entity was assumed.
Homozygosity mapping in this family assigned the gene to a 26. 8-cM region on the chromosome band 8q21. 3 -22. 1, between the microsatellites at D8S270 and D8S514. The maximum two-point LOD score was found for marker at D8S267 (Zmax = 3.. 237 at Omax = 0. 00). Intriguingly enough, the identified gene region overlaps the refined gene region for Cohen syndrome (COH1) [Kolehmainen et al., 1997  Euro J Hum Genet 5  206-213]. This fact encourages the hypothesis that the described kindred segregates for a variant of Cohen syndrome and suggests a redefinition of its phenotype 
