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Cryptic familial t(11;18)(q25;q23) incidentally detected by interphase FISH
Author(s) -
Schultz Ln,
Schmidt P,
Tabor A,
Bryndorf T,
Christensen B,
Lundsteen C
Publication year - 2001
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.1399-0004.2001.590411.x
Subject(s) - chromosomal translocation , subtelomere , karyotype , biology , genetics , chorionic villus sampling , mentally retarded , locus (genetics) , autosome , prenatal diagnosis , chromosome , interphase , fetus , pregnancy , psychology , gene , developmental psychology
During a prospective prenatal study of numerical abnormalities of chromosomes 13, 18, 21, X and Y using locus‐specific probes, we incidentally found a case with only one signal for chromosome 18 per cell in a chorionic villus sampling (CVS) associated with an otherwise apparently normal G‐banded karyotype. This led us to discover a cryptic t(11;18) segregating in a four‐generation family. The CVS was performed because of mental retardation in the brother to the father of the fetus. A subtelomeric chromosome 18 probe revealed one signal on 18qter and one on 11qter of the father. Thus the father had a balanced reciprocal t(11;18) in spite of the apparently normal G‐banded karyotype. Using the same probes, we found an unbalanced translocation 46,XX,‐18,+der (18)t(11;18)‐(q25;q23)pat in the fetus. Further investigation of the family showed the translocation in balanced and unbalanced form in four generations in mentally normal and retarded individuals, respectively. The study emphasizes the need for a follow‐up with molecular cytogenetic techniques in dysmorphic and retarded children.