ABSTRACT
OBJECTIVE: To describe auxologic, physical, and behavioral features in a large cohort of males with 47,XYY (XYY), ages newborn to young adult. STUDY DESIGN: This is a cross-sectional descriptive study of male subjects with XYY who were evaluated at 1 of 2 specialized academic sites. Subjects underwent a history, physical examination, laboratory testing, and cognitive/behavioral evaluation. RESULTS: In 90 males with XYY (mean age 9.6 ± 5.3 years [range 0.5-36.5]), mean height SD was above average (1.0 ± 1.2 SD). Macrocephaly (head circumference >2 SD) was noted in 28/84 (33%), hypotonia in 57/90 (63%), clinodactyly in 47/90 (52%), and hypertelorism in 53/90 (59%). There was testicular enlargement for age (>2 SD) in 41/82 (50%), but no increase in genital anomalies. No physical phenotypic differences were seen in boys diagnosed prenatally vs postnatally. Testosterone, luteinizing hormone, and follicle stimulating hormone levels were in the normal range in most boys. There was an increased incidence of asthma, seizures, tremor, and autistic spectrum disorder (ASD) compared with the general population rates. Prenatally diagnosed boys scored significantly better on cognitive testing and were less likely to be diagnosed with ASD (P < .01). CONCLUSIONS: The XYY phenotype commonly includes tall stature, macrocephaly, macroorchidism, hypotonia, hypertelorism, and tremor. Physical phenotypic features were similar in boys diagnosed prenatally vs postnatally. Prenatal diagnosis was associated with higher cognitive function and less likelihood of an ASD diagnosis.
Subject(s)
Sex Chromosome Disorders/diagnosis , Sex Chromosome Disorders/genetics , XYY Karyotype/diagnosis , XYY Karyotype/genetics , Adolescent , Adult , Child , Child Behavior , Child, Preschool , Cognition Disorders/diagnosis , Cohort Studies , Cross-Sectional Studies , Hand Deformities/diagnosis , Humans , Infant , Male , Megalencephaly/diagnosis , Muscle Hypotonia/diagnosis , Neuropsychological Tests , Phenotype , Social Class , Surveys and Questionnaires , Young AdultABSTRACT
OBJECTIVE: To contrast the behavioral and social phenotypes including a screen for autistic behaviors in boys with 47,XYY syndrome (XYY) or 47,XXY Klinefelter syndrome (KS) and controls and investigate the effect of prenatal diagnosis on the phenotype. METHODS: Patients included 26 boys with 47,XYY, 82 boys with KS, and 50 control boys (ages 4-15 years). Participants and parents completed a physical examination, behavioral questionnaires, and intellectual assessments. RESULTS: Most boys with XYY or KS had Child Behavior Checklist parental ratings within the normal range. On the Child Behavior Checklist, mean problem behaviors t scores were higher in the XYY versus KS groups for the Problem Behavior, Externalizing, Withdrawn, Thought Problems, and Attention Problems subscales. On the Conners' Parent Rating Scale-Revised, the XYY versus KS group had increased frequency of hyperactive/impulsive symptoms (P < .006). In addition, 50% and 12% of the XYY and KS groups, respectively, had scores >15 for autism screening from the Social Communication Questionnaire. For the boys with KS, prenatal diagnosis was associated with fewer problem behaviors. CONCLUSIONS: A subset of the XYY and KS groups had behavioral difficulties that were more severe in the XYY group. These findings could guide clinical practice and inform patients and parents. Boys diagnosed with XYY or KS should receive a comprehensive psychoeducational evaluation and be screened for learning disabilities, attention-deficit/hyperactivity disorder, and autism spectrum disorders.
