Cohen syndrome is characterised by
mental retardation,
postnatal microcephaly,
facial dysmorphism, pigmentary
retinopathy,
myopia, and intermittent
neutropenia.
Mutations in
COH1 (
VPS13B) have been found in patients with
Cohen syndrome from diverse ethnic origins. We have carried out
mutation analysis in twelve novel patients with
Cohen syndrome from nine families. In this series, we have identified 13 different
mutations in
COH1, twelve of these are novel including six
frameshift mutations, four
nonsense mutations, two
splice site mutations, and a one-codon deletion. Since different transcripts of
COH1 have been reported previously, we have analysed the expression patterns of
COH1 splice variants. The transcript variant NM_152564 including
exon 28b showed ubiquitous expression in all examined
human tissues. In contrast,
human brain and
retina showed differential splicing of
exon 28 (NM_017890). Moreover, analysis of
mouse tissues revealed ubiquitous expression of Coh1 homologous to human NM_152564 in all examined tissues but no
prevalent alternative splicing. (c) 2008 Wiley-Liss, Inc.
