Genetic Mapping of X-linked Albinism-Deafness Syndrome (ADFN) to
Xq26.3-q27.I
Y. Shiloh, G. Litvak, Y. Ziv, T. Lehner, L. Sandkuyl,
M. Hildesheimer, V. Buchris, F.P.M. Cremers, P. Szabo,
B.N. White, J.J.A. Holden, J. Ott
American Journal of Human Genetics , 47(1),20--27 (1990 Jul)
Abstract
X-linked albinism-deafness syndrome (ADFN) was described in one
Israeli Jewish family and is characterized by congenital nerve
deafness and piebaldness. The ADFN mutation probably affects the
migration of neural crest-derived precursors of the melanocytes. As
a first step toward identifying the ADFN gene, a linkage study was
performed to localize the disease locus on the X chromosome. The
family was found to be informative for 11 of 107 RFLPs along the X,
and two-point analysis showed four of them--factor 9 (F9), DXS91,
DXS37, and DNF1--to have definite or suggestive linkage with ADFN.
Multipoint linkage analysis indicated two possible orders within
this cluster of loci, neither of which was preferable. In both
orders F9 was the most distal, and the best estimate for the
location of ADFN was between F9 and the next proximal marker (8.6 cM
from F9 [Z = 8.1] or 8.3 cM from F9 [Z = 7.9]). These results
suggest that the ADFN is at Xq26.3-q27.1. Disagreement between our
data and previous localization of DXS91 at Xq11-q13 was resolved by
hybridization of the probe pXG-17, which detects the DXS91 locus, to
a panel of somatic cell hybrids containing different portions of the
X chromosome. This experiment showed that this locus is definitely
at Xq24-q26. Together with the linkage data, our results place DXS91
at Xq26 and underscore the importance of using more than one mapping
method for the localization of molecular probes.
