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Growth of heterokaryotic monozygotic twins discordant for Ullrich–Turner syndrome during the first years of life
Author(s) -
Rohrer T.R.,
Gassmann K.F.,
Rauch A.,
Pfeiffer R.A.,
Doerr H.G.
Publication year - 2004
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.20446
Subject(s) - karyotype , heterokaryon , monozygotic twin , biology , turner syndrome , chromosomal abnormality , identical twins , buccal swab , chromosome , genetics , x chromosome , endocrinology , gene , mutant
The rare observation of different karyotypes in monozygotic (MZ) twins, i.e., heterokaryotic monozygosity, occurs due to chromosomal aberration in one of the twins after separation of the embryos. We report on the differences of heterokaryotic MZ Turkish twins who are discordant for Ullrich–Turner syndrome. Chromosomal analyses from peripheral lymphocytes revealed a 45,X/46,XX mosaicism in both twins. FISH analyses of buccal smears showed 99% of nuclei 45,X in twin A and 98% of nuclei 46,XX in twin B. These results are consistent with a non‐mosaic 45,X and 46,XX karyotype, respectively. The girls showed a different growth pattern in the first years. As their genotype should be identical except for the number of X chromosomes, the difference in phenotype may be a pure result of loss of one X chromosome in the affected girl. Special interest is set on the spontaneous and growth hormone induced growth of the twins. © 2004 Wiley‐Liss, Inc.