A new locus for Seckel syndrome on chromosome 18p11.31-q11.2

Seckel syndrome (MIM 210600) is a rare autosomal recessive disorder with a heterogeneous appearance. Key features are growth retardation, microcephaly with mental retardation, and a characteristic 'bird-headed' facial appeara nce. We have performed a genome-wide linkage scan in a consanguineous famil y of Iraqi descent. By homozygosity mapping a new locus for the syndrome wa s assigned to a similar to 30 cM interval between markers D18S78 and D18S86 6 with a maximum multipoint lod score of 3.1, corresponding to a trans-cent romeric region on chromosome 18p11.31-q11.2. This second locus for Seckel s yndrome demonstrates genetic heterogeneity and brings us a step further tow ards molecular genetic delineation of this heterogeneous condition.