ABSTRACT
Partial monosomy 10q25.2----qter, detected in a newborn baby with multiple congenital abnormalities, was found to be derived from a balanced maternal translocation t(6;10)(q27;q25.2). The pedigree of six generations of the family is presented. In an extensive cytogenetic study of this family, the chromosome complements of 57 subjects, potentially capable of carrying some form of this translocation, were analysed. A total of 14 male carriers (four obligatory) and 14 female carriers (three obligatory) of this translocation was found. Partial trisomy 10q25.2----qter, associated with severe mental retardation, occurred in nine cases, eight males and one female. Two of these eight males were detected prenatally and subsequently therapeutically aborted. The phenotypes of the family members with partial trisomy 10q25.2----qter are compared to each other and to those reported in publications. No further cases of partial monosomy 10q25.2----qter were encountered. A review of published reports of partial monosomy and partial trisomy 10qter is given. The apparent absence of infertility, the occurrence of many first trimester miscarriages, and the marked sex ratio are discussed.
Subject(s)
Abnormalities, Multiple/genetics , Chromosomes, Human, Pair 10 , Chromosomes, Human, Pair 6 , Intellectual Disability/genetics , Translocation, Genetic , Adolescent , Adult , Chromosome Banding , Female , Genetic Carrier Screening , Humans , Infant, Newborn , Karyotyping , Male , Pedigree , South AfricaABSTRACT
Five cases in which phenotypic abnormalities were found in association with apparent balanced chromosomal translocations are described. In 3 patients, one of the parents was found to be a carrier of the same translocation. In a further patient, the translocation was shown to be de novo and in the remaining patient the father was not available for chromosome studies. In a review of the literature the breakpoints in 36 familial balanced translocations were compared with 40 de novo translocations (including the present cases) all associated with phenotypic abnormalities. No common translocation was found in these groups, but it was observed that chromosomes 4 and 5 were significantly more involved in de novo translocations than in familial translocations. The possible aetiology and implications for prenatal diagnoses are discussed.
Subject(s)
Chromosome Aberrations/genetics , Translocation, Genetic , Adolescent , Child , Child, Preschool , Chromosome Banding , Chromosome Disorders , Female , Humans , Infant, Newborn , Karyotyping , Male , PhenotypeABSTRACT
The Holt-Oram syndrome is an autosomal dominant disease with 100% penetrance. No correlation exists between the maternal clinical expression and that of the affected offspring. The syndrome includes a wide range of cardiac and skeletal malformations. Real-time ultrasound, with a detailed study of the fetal heart and skeletal system, can play a crucial role in the counselling of affected pregnant women. This study describes the ultrasonographic findings of 2 affected fetuses at risk (at 34 and 14 weeks' gestational age). Ultrasonography detected and correctly estimated the severity of the cardiac and skeletal expressions.
