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Double supernumerary isodicentric chromosomes derived from 15 resulting in partial hexasomy
Author(s) -
Qumsiyeh Mazin B.,
Rafi Syed K.,
Sarri Catherine,
Grigoriadou Maria,
Gyftodimou Jolanda,
Pandelia Effie,
Laskari Hara,
Petersen Michael B.
Publication year - 2002
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.10050
Subject(s) - small supernumerary marker chromosome , supernumerary , genetics , angelman syndrome , biology , psychomotor retardation , phenotype , chromosome , hypotonia , karyotype , gene , medicine , anatomy , pathology , alternative medicine
We report two unrelated patients each with two supernumerary marker chromosomes (SMCs) derived from chromosome 15, and thus resulting in partial hexasomy. Hexasomy in the one case (family 1) was diagnosed at prenatal diagnosis and did not include the Prader–Willi/Angelman critical region (PWACR). The double SMCs were also found in the mother, the pregnancy continued to term, and an apparently phenotypically normal child was born. This represents the first report of transmission of double SMCs from mother to child. In the second case (family 2), the hexasomy did include the PWACR and was de novo in origin. This patient manifested severe psychomotor retardation, clefting of the soft palate, hypotonia, seizure‐like episodes, and other phenotypic features. The aberrant phenotype is attributable to the hexasomy for the PWACR gene loci. The normal homologs of chromosome 15 proved to be biparental in origin while the two SMCs appeared maternal. © 2003 Wiley‐Liss, Inc.