Primary autosomal recessive microcephaly: MCPH5 maps to 1q25-q32

Primary microcephaly is thought to result from genetic defects of the devel opmental program that generates large brain hemispheres in humans. Autosoma l recessive inheritance is likely in most familial cases, and four loci wer e recently mapped by homozygosity. We report homozygosity mapping of a new locus, MCPH5, with a maximum multipoint LOD score of 3.51 at marker D1S1723 , in a family of Turkish origin. The minimal critical region spans 11.4 cM between markers D1S384 and D1S2655, at 1q25-q32, and encompasses the cytoge netic breakpoints of chromosomal aberrations previously reported in unrelat ed patients with microcephaly.