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Intrachromosomal triplication for the distal part of chromosome 15q
Author(s) -
Schluth C.,
Mattei M. G.,
MigRavix C.,
Salman S.,
Alembik Y.,
Willig J.,
Ginglinger E.,
Jeandidier E.
Publication year - 2005
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.30745
Subject(s) - tetrasomy , karyotype , arachnodactyly , biology , chromosome , genetics , chromosome 15 , telomere , chromosomal rearrangement , gene duplication , medicine , dna , marfan syndrome , gene
We report the case of a boy whose karyotype at birth showed additional material on one chromosome 15. He underwent treatment for unilateral nephroblastoma at 6 years old. At 23 years old, he presented with body asymmetry, facial dysmorphism, arachnodactyly, severe scoliosis, and mental retardation. Molecular cytogenetic analyses of peripheral lymphocytes demonstrated a complex mosaic with three clones. A major cell lineage (68%) showed a chromosome 15 with additional material fused to its telomere long arm that was constituted by an inverted duplicated 15q24.3‐qter segment. Therefore, the resulting add(15)(q) harbored an intrachromosomal triplication with the middle segment being inverted in orientation. A minor cell lineage (7%) showed an abnormal chromosome 3 resulting from a telomeric fusion between its short arm and an inverted duplicated 15q24.3‐qter segment. The third cell lineage (25%) showed a normal 46,XY constitution. Finally, this resulted in tetrasomy for the distal 15q24.3‐qter region in 75% of the patient's lymphocytes. To our knowledge, distal 15q tetrasomy is rare and only eight cases have been reported in the literature, all due to a supernumerary analphoid marker consisting of an inverted duplication. We report here the first observation of distal 15q tetrasomy associated with a 46 chromosomes constitution. We compare the phenotype of our patient to previous cases of distal tetrasomy 15q and discuss the mechanisms underlying this chromosomal rearrangement. © 2005 Wiley‐Liss, Inc.