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An extra idic(21)(q22.1) in a child with some features of Down’s syndrome
Author(s) -
GutiérrezAngulo M,
Ramos Al,
Dávalos N,
SánchezCorona J,
Rivera H
Publication year - 1999
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1034/j.1399-0004.1999.550309.x
Subject(s) - hypotonia , tetrasomy , phenotype , karyotype , genetics , down syndrome , aneuploidy , biology , chromosome , gene
A 30‐month‐old boy with mental retardation, hypotonia, joint hyperlaxity, Brushfield spots, open mouth, distal axial triradius t′′, and ulnar loops on both forefingers was found to have a 47,XY,+psu idic(21)(q22.1).ish psu idic(21)(q22.1)(D13Z1/D21Z1++,ETS2−) karyotype. The patient’s phenotype, with only some Down’s syndrome (DS) features, is probably related to his disomy for most or all of the critical region 21q22.2→q22.3 and agrees with the current notion that certain DS features may also result from 21q proximal duplications. The phenotypical comparison with 2 other patients with a similar extra idic(21) reveals some discrepancies, which may be related to the inherent clinical variability of similar imbalances; yet, a real difference between the tetrasomic segments cannot be excluded. Noticeably, all 3 patients with 21q proximal tetrasomy did not have cardiac defect and exhibited none or just one out of the five other DS phenotypic features attributed to a single gene or cluster on distal 21q22.