<abstract xmlns="http://www.w3.org/1999/xhtml"><p> Pentasomy X is an extremely rare sex chromosome abnormality, a condition that only affects females, in which three more X chromosomes are added to the normally present two chromosomes in females. We investigated the novel clinical findings in a 1-year-old female baby with pentasomy X, and determined the parental origins of the X chromosomes. Our case had thenar atrophy, postnatal growth deficiency, developmental delay, mongoloid slant, microcephaly, ear anomalies, micrognathia and congenital heart disease. A conventional cytogenetic technique was applied for the diagnosis of the polysomy X, and quantitative fluorescent polymerase chain reaction (QF-PCR) using 11 inherited short tandem repeat (STR) alleles specific to the chromosome X for the determination of parental origin of X chromosomes. A cytogenetic evaluation revealed that the karyotype of the infant was 49,XXXXX. Comparison of the infant’s features with previously reported cases indicated a clinically recognizable specific pattern of malformations referred to as the pentasomy X syndrome. However, to the best of our know-ledge, this is the first report of thenar atrophy in a patient with 49,XXXXX. The molecular analysis suggested that four X chromosomes of the infant originated from the mother as a result of the non disjunction events in meiosis I and meiosis II. We here state that the clinical manifestations seen in our case were consistent with those described previously in patients with pentasomy X. The degree of early hypotonia constitutes an important early prognostic feature in this syndrome. The pathogenesis of pentasomy X is not clear at present, but it is thought to be caused by successive maternal non disjunctions.</p></abstract>

Pentasomy X is an extremely rare sex chromosome abnormality, a condition that only affects females, in which three more X chromosomes are added to the normally present two chromosomes in females. We investigated the novel clinical findings in a 1-year-old female baby with pentasomy X, and determined the parental origins of the X chromosomes. Our case had thenar atrophy, postnatal growth deficiency, developmental delay, mongoloid slant, microcephaly, ear anomalies, micrognathia and congenital heart disease. A conventional cytogenetic technique was applied for the diagnosis of the polysomy X, and quantitative fluorescent polymerase chain reaction (QF-PCR) using 11 inherited short tandem repeat (STR) alleles specific to the chromosome X for the determination of parental origin of X chromosomes. A cytogenetic evaluation revealed that the karyotype of the infant was 49,XXXXX. Comparison of the infant’s features with previously reported cases indicated a clinically recognizable specific pattern of malformations referred to as the pentasomy X syndrome. However, to the best of our know-ledge, this is the first report of thenar atrophy in a patient with 49,XXXXX. The molecular analysis suggested that four X chromosomes of the infant originated from the mother as a result of the non disjunction events in meiosis I and meiosis II. We here state that the clinical manifestations seen in our case were consistent with those described previously in patients with pentasomy X. The degree of early hypotonia constitutes an important early prognostic feature in this syndrome. The pathogenesis of pentasomy X is not clear at present, but it is thought to be caused by successive maternal non disjunctions.

Report of a New Case With Pentasomy X and Novel Clinical Findings

Department of Medical Biology and Genetics, Faculty of Medicine, Çukurova University, 01330 Saricam, Adana, Turkey. Tel: +90-322-338-7140. Fax: +90-322-338-6572

Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey

Department of Pediatrics, Çukurova University, Faculty of Medicine, Adana, Turkey

Balkan Journal of Medical Genetics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

{"article-title":"Report of a New Case With Pentasomy X and Novel Clinical Findings"}

Pentasomy X is an extremely rare sex chromosome abnormality, a condition that only affects females, in which three more X chromosomes are added to the normally...

Report of a New Case With Pentasomy X and Novel Clinical Findings

Published Online: Dec 30, 2015

Page range: 85 - 92

DOI: https://doi.org/10.1515/bjmg-2015-0010

Keywords
Clinical findings, parental origin, pentasomy X syndrome, quantitative fluorescentpolymerase chain reaction (QF-PCR), short tandem repeat (STR) markers, 49,XXXXX

© Balkan Journal of Medical Genetics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Report of a New Case With Pentasomy X and Novel Clinical Findings

Published Online: Dec 30, 2015

Page range: 85 - 92

DOI: https://doi.org/10.1515/bjmg-2015-0010

KeywordsClinical findings, parental origin, pentasomy X syndrome, quantitative fluorescentpolymerase chain reaction (QF-PCR), short tandem repeat (STR) markers, 49,XXXXX

© Balkan Journal of Medical Genetics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
Clinical findings, parental origin, pentasomy X syndrome, quantitative fluorescentpolymerase chain reaction (QF-PCR), short tandem repeat (STR) markers, 49,XXXXX