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X chromosome inactivation patterns in Russell–Silver syndrome patients and their mothers
Author(s) -
Beever Christy L.,
Peñaherrera Maria S.,
Langlois Sylvie,
Robinson Wendy R.
Publication year - 2003
Publication title -
american journal of medical genetics part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.064
H-Index - 112
eISSN - 1552-4833
pISSN - 1552-4825
DOI - 10.1002/ajmg.a.20317
Subject(s) - rss , uniparental disomy , genetics , biology , x chromosome , allele , skewed x inactivation , chromosome , x inactivation , karyotype , gene , computer science , operating system
Russell–Silver syndrome (RSS) is a disorder characterized by pre‐ and post‐natal growth deficiency, triangular facies, relative macrocephaly, and body asymmetry. Maternal uniparental disomy for chromosome 7 has been found in approximately 10% of RSS cases, while the cause in the remaining cases is unknown. Although most cases of RSS are sporadic, at least 25 families have been reported with familial RSS and inheritance patterns of RSS consistent with an X‐linked dominant mutation. Thus, we hypothesized that skewed X‐chromosome inactivation (XCI) could be increased in some females with RSS as a consequence of a tendency to have the mutant allele on the predominantly active chromosome. Alternatively, unaffected mothers of children with RSS may tend to be skewed due to preferential inactivation of the mutant allele. In support of this last hypothesis, a significant increase in extremely skewed XCI (>95%) was found in mothers of children with RSS (4 of 21, 19%) compared to controls (2 of 101, 2%) ( P = 0.008). However, an increase in skewed XCI was also observed in female patients who had unexplained short stature but did not fulfill the criteria for RSS (3 of 17, 18%) ( P = 0.02), but not in those diagnosed as RSS (0 of 7, n.s.). Different mechanisms may underlie the increase in skewing in each group, possibly being due to different X‐linked mutations or growth restriction during very early in utero development. © 2003 Wiley‐Liss, Inc.