title: Report of a new case with pentasomy X and novel clinical findings.
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.
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: O
authors.initials: O
authors.lastname: Demirhan
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: N
authors.initials: N
authors.lastname: Tanriverdi
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: M B
authors.initials: MB
authors.lastname: Yilmaz
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Kocaturk-Sel
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: N
authors.initials: N
authors.lastname: Inandiklioglu
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: U
authors.initials: U
authors.lastname: Luleyap
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Akbal
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: G
authors.initials: G
authors.lastname: Comertpay
authors.affiliation: Department of Medical Biology and Genetics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: T
authors.initials: T
authors.lastname: Tufan
authors.affiliation: Department of Pediatrics, Çukurova University, Faculty of Medicine, Adana, Turkey.
authors.forename: O
authors.initials: O
authors.lastname: Dur
keywords: 49,XXXXX; Clinical findings; parental origin; pentasomy X syndrome; quantitative fluorescent-polymerase chain reaction (QF-PCR); short tandem repeat (STR) markers