Endocrine Abstracts

Introduction: 48, XXYY is a rare sex chromosome aneuploidy, being estimated to occur in 1:18000–1:40000 male births. Phenotypically it was considered a variant of Klinefelter syndrome (47,XXY), but currently, due to mental deficiency and behavioural characteristics associated, it’s considered to be a separated genetic condition.

Case report: We report a case of a 8-year-old boy, first child of a young non-consanguineous couple, born at term. Due to minor dysmorphic facial features, hypospadias and bilateral talus valgus, a genetic test was conducted and the karyotype identified was 48,XXYY. He was frequently hospitalized for upper respiratory infections, gastro-enteritis, recurrent otitis. He was diagnosed with viral induced asthma and IgA and IgG subclass deficiencies, developing food and medication allergies. Physical examination revealed normal height and weight, dysmorphic facial features (thick eyebrows, hypertelorism, mongoloid slant of the eyes, convergent strabismus, thin lips, dental problems), bifid scrotum, hypospadias, sacral sinus, clinodactyly of the fifth finger, bilateral talus valgus surgically corrected. Neuropsychiatric evaluation revealed borderline mental retardation, delayed speaking, aggressive behaviour, learning difficulties. The endocrinologic consult showed a normal thyroid axe, with a normal-low testosterone level (<0.025 ng/ml) associated with a FSH level of 0.98 mUI/ml (0.4–3.8) and LH level <0.1 mUI/ml (0–3,8). Thyroid ultrasound was normal, testicular ultrasound revealed hypoechoic testis, the X-ray of the hand revealed delayed bone age.

Conclusions: 48,XXYY was described as a variant of 47,XXY syndrome. It is very important to distinguish the two syndromes regarding the associated medical conditions (as in our case – asthma, food allergies, dental problems, strabismus, recurrent otitis, frequent upper respiratory infections), cognitive and behavioural problems, learning difficulties which are more frequently correlated with 48,XXYY syndrome. Due to complexity and specific features of this particular syndrome, it is recommended a thorough evaluation and a different therapeutic attitude for each case.