Untersuchungen zu familiären und rassespezifischen ...

MITF as candidate for deafness in Dalmatian dogs 115
6 A role of the microphthalmia-associated transcription
factor (MITF) in congenital sensorineural deafness and
eye pigmentation in Dalmatian dogs
Key words deafness; blue eyes; Dalmatian dog; microphthalmia transcription factor;
association
Summary
MITF (microphthalmia-associated transcription factor) is involved in white spotting
and deafness associated with lack of pigmentation in human and mice. In the present
study, we employed MITF-associated markers to evaluate MITF as a candidate for
canine congenital sensorineural deafness (CCSD) in Dalmatian dogs. We performed
an association study using MITF flanking and intragenic markers for 88 Dalmatian
dogs of different hearing and eye pigmentation status. A significant association was
identified for MITF-related markers with CCSD and blue iris color. We conclude that
MITF might play a role in CCSD and blue eye colour in Dalmatian dogs.
Introduction
The pigmentation of the Dalmatian dog is described to be white, caused by the
extreme-white allele (s w ) of the white spotting locus (S), with black or brown spots
deriving from the flecking and ticking loci (Little et al. 1957). The S locus was mapped
to a region of ~100 kb contained within the pigmentation related gene
microphthalmia-associated transcription factor (MITF) (Karlsson et al. 2007). MITF
was localized to dog chromosome 20q13 using fluorescence in situ hybridization
(Rak & Distl 2005). The location of MITF (GeneID: 415126) on dog genome
assembly 2.1 is at 24.85-24.88 Mb. Dalmatian puppies are born completely white,
except for the infrequent appearance of congenital pigmented patches around the
eyes (monocles) or at the ears. Blue iris color is also an occasional finding in
Dalmatian dogs. Dogs of this breed are more often affected by canine congenital