Effect of Ascertainment and Genetic Features on the Phenotype of Klinefelter Syndrome

Martha P D Zeger, Andrew R. Zinn, Najiba Lahlou, Purita Ramos, Karen Kowal, Carole Samango-Sprouse, Judith L. Ross

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

Objective: To describe the Klinefelter Syndrome(KS) phenotype during childhood in a large cohort. Study design: Clinical assessment, measurement of hormonal indices of testicular function, and parent of origin of extra X chromosome were assessed in a cross-sectional study of 55 boys with KS, aged 2.0 to 14.6 years, at an outpatient center. Results: Mean height and body mass index SD scores (SDS ± SD) were 0.9 ± 1.3 and 0.4 ± 1.4, respectively. Mean penile length and testicular volume SDS were -0.5 ± 0.9 and -0.9 ± 1.4. Testosterone levels were in the lowest quartile of normal in 66% of the cohort. Other features included clinodactyly (74%), hypertelorism (69%), elbow dysplasia (36%), high-arched palate (37%), hypotonia (76%), and requirement for speech therapy (69%). Features were similar in boys in whom the diagnosis was made prenatally versus boys in whom the diagnosis was made postnatally. There was no evidence for a phenotypic effect of parent of origin of the extra X chromosome. Conclusions: Boys with KS commonly have reduced penile length and small testes in childhood. The phenotype in boys with KS does not differ according to ascertainment or origin of the extra X chromosome. Boys with KS may be identified before puberty by tall stature, relatively decreased penile length, clinodactyly, hypotonia, and requirement for speech therapy.

Original languageEnglish (US)
Pages (from-to)716-722
Number of pages7
JournalJournal of Pediatrics
Volume152
Issue number5
DOIs
StatePublished - May 1 2008

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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