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First non‐mosaic case of isopseudodicentric chromosome 18 (psu idic(18)(pter → q22.1::q22.1 → pter) Is associated with multiple congenital anomalies reminiscent of trisomy 18 and 18q− syndrome
Author(s) -
Meins M.,
Böhm D.,
Großmann A.,
Herting E.,
Fleckenstein B.,
Fauth C.,
Speicher M.R.,
Schindler R.,
Zoll B.,
Bartels I.,
Burfeind Peter
Publication year - 2003
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.20644
Subject(s) - derivative chromosome , biology , chromosome 18 , monosomy , karyotype , trisomy , chromosome , chromosomal translocation , chromosome 7 (human) , genetics , microbiology and biotechnology , gene
Isopseudodicentric chromosome 18 is very rare and results in a combination of partial trisomy and partial monosomy of chromosome 18. We report here a hypotrophic newborn with a lateral cleft lip and palate and multiple craniofacial dysmorphisms, a combined heart defect, unilateral hypoplasia of the kidney, bilateral aplasia of thumbs, and generalized contractures. Cytogenetic analysis revealed an isopseudodicentric chromosome 18 with breakpoint in 18q (46,XX,psu idic(18)(pter → q22.1::q22.1 → pter)). The isopseudodicentric chromosome 18 was observed in 100% of blood lymphocytes and umbilical cord fibroblasts, thus indicating a non‐mosaic finding of the isopseudodicentric chromosome in the child. An elongated derivative chromosome 18 had also been found prenatally in amniotic cells. In contrast, a terminal deletion (18q−) was detected in placental cell cultures. The breakpoint was mapped to a 0.9 Mb region on 18q22.1 (located 64.8–65.7 Mb from the telomere of the p‐arm) by a novel quantitative PCR approach with SYBR green detection. The results indicate an identical breakpoint of the isopseudodicentric chromosome 18 in the child and the 18q− chromosome in the placenta. To our knowledge this is the first report that a fetus carrying an isopseudodicentric chromosome 18 with breakpoint in 18q (46,XX,psu idic(18)(pter → q22.1::q22.1 → pter)) in non‐mosaic form can be viable, but is associated with severe congenital malformations of the child. © 2003 Wiley‐Liss, Inc.