A SMALL (sSMC) CHROMOSOME 22 DUE TO A MATERNAL TRANSLOCATION BETWEEN CHROMOSOMES 8 AND 22: A CASE REPORT

Mundhofir, Farmaditya EP and A.J.A. Kooper, A.J.A. Kooper and Winarni, Tri Indah and A.P.T. Smith, A.P.T. Smith and Faradz, Sultana M.H. and B.C.J. Hamel, B.C.J. Hamel (2010) A SMALL (sSMC) CHROMOSOME 22 DUE TO A MATERNAL TRANSLOCATION BETWEEN CHROMOSOMES 8 AND 22: A CASE REPORT. Journal of Genetic Counseling, 21 (1). pp. 99-108. ISSN 1059-7700

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Abstract

Summary: A small supernumerary marker (sSMC) chromosome 22 due to a maternal translocation between chromosomes 8 and 22: a case report: We report on a boy with partial trisomies for chromosomes 8 and 22 caused by the presence of a small supernumerary marker chromosome (sSMC), a der(22)t(8;22)(p22;q11.21), inherited from a t(8;22)(p22;q11.21) translocation carrier mother. He has mild mental retardation, unability to speak distinct words and several minor anomalies i.e. high forehead and hairline, telecanthus, upslanting palpebral fissures, depressed nasal bridge, nail hypoplasia, toe position anomaly and 5th finger clinodactyly. He has two maternal uncles and one maternal aunt with mental retardation. G-banding technique showed 47,XY,+mar whilst his mother’s karyotype showed a balanced reciprocal translocation between the chromosomes 8 and 22. Fluorescence In Situ Hybridization (FISH) technique with probes for centromere 22 and 8pter were used to detect the origin of marker chromosome and confirmed the marker chromosome in the proband showing to be extra chromosomal material originated from chromosome 8 and 22. Additional genome wide microarray analysis, using the Affymetrix Nspl 250K SNP array platform was performed to further characterize the marker chromosome and resulted in a der(22)t(8;22)(p22;q11.21). Furthermore, cytogenetic analysis of three affected family members showed the same unbalanced translocation, due to 3:1 meiotic segregation. This indicated the viability of this unbalanced pattern and combined with the recurrent miscarriages by the proband’s mother, the mechanism of transmitting extrachromosomal material is probably not a random process. Since, there is no similar translocation (8p;22q) reported and the chromosomal translocation largely exists of additional 8p22-8pter we compare the clinical outcomes with reported cases of 8p22-8pter triplication, although there is a part of genetic material derived from chromosome 22 present. This unique familial chromosome translocation case from Indonesia will give insight in the underlying mechanism of this recurrent chromosomal abnormality and clinical features of the patients will be compared to previously published cases. Key-words: Supernumerary marker chromosome – der(22)t(8;22)(p22;q11.21) – Partial trisomy chromosomes 8 and 22 – 3:1 meiotic segregation.

Item Type:Article
Uncontrolled Keywords:Supernumerary marker chromosome – der(22)t(8;22)(p22;q11.21) – Partial trisomy chromosomes 8 and 22 – 3:1 meiotic segregation
Subjects:Q Science > QH Natural history > QH426 Genetics
Divisions:Faculty of Medicine > Department of Medicine
Faculty of Medicine > Department of Medicine
ID Code:66732
Deposited By:Ms Lutfiatun Heni
Deposited On:21 Nov 2018 09:48
Last Modified:21 Nov 2018 10:06

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