Biology Reference
In-Depth Information
briefly discuss some of the deletion syndromes that have hearing loss as a
frequent clinical finding.
2.2.3.1 1p36 Deletion Syndrome
1p36 deletion syndrome is a relatively newly recognized microdeletion syn-
drome (Fig. 5.7A). Because the deletion is usually fairly small, and in a large,
lightly staining portion of the terminus of the short arm of chromosome 1,
FIGURE 5.7. Microdeletion syndromes that have hearing loss as a component of the
syndrome. (A) Ideogram of chromosome 1 showing the region of deletion on distal
1q that causes 1p36 deletion syndrome (Wu et al. 1999). (B) The regions on chro-
mosomes 22 and 10 that are deleted in DiGeorge/velocardiofacial syndromes types
one
and
two
, respectively. (C) The region of the short arm of chromosome 17 that
is deleted in Smith-Magenis syndrome. The nonsyndromic hearing disorder DFNB3
maps to this region; mutations in the gene for
MYO15
underlie this disorder (Wang
et al. 1998).
