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A case of de novo trisomy 12p syndrome
Author(s) -
Tayel Shawky,
McCorquodale M. M.,
Rutherford T.,
Kurczynski T. W.,
AbdelAziz Adel M.,
ElGabaldy Farid,
Sharaf E. A.
Publication year - 1989
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 - 10.1111/j.1399-0004.1989.tb02958.x
Subject(s) - trisomy , hypertelorism , hypotonia , pectus excavatum , macroglossia , gene duplication , locus (genetics) , genetics , biology , medicine , anatomy , pediatrics , pathology , gene , tongue
A case of pure 12p trisomy was discovered in a 14‐year‐old boy during a cytogenetic survey of Egyptian students attending a school for mentally retarded children. The patient had a normal birth weight but later showed developmental delay. Clinical examination at 14 years of age revealed a high bulging forehead, broad and flat nasal bridge, large mouth with everted lower lip, folded upper ear helix with protuberant antihelix, pectus excavatum, undescended testes, flat feet, generalized hypotonia and moderate mental retardation. Chromosomes analyzed from blood lymphocytes showed an enlarged short arm with an additional band on one of the no. 12 chromosomes. The duplicated chromosomal material extended from 12pter→p12.2, including the LDH‐B locus, which showed a gene‐dosage effect. This extra chromosomal material arose de novo by tandem duplication. The parents' chromosomes were normal.