Endocrine Abstracts

Within the group of gonosomal aneuploidy, the 47,XXY Klinefelter syndrome is a well-known chromosomal anomaly with a clearly delineated phenotype. Since the 48,XXYY polysomy is rather rare and associated with hypogenitalism, it has often been considered as a variant of the Klinefelter syndrome. Nevertheless, several differences have been reported, in particular the greater severity and prevalence of mental retardation and psychiatric illness in patients with a 48,XXYY syndrome. Although the 48,XXYY is now considered to be a distinct clinical and genetic entity, there is very little data available in the literature, especially about adults. Moreover, endocrine studies are rarely performed.

To our knowledge, this is the first report of a case of an adult with the 48,XXYY syndrome concomitant with type 2 diabetes. The diabetes is probably related to a metabolic syndrome associated with the truncular obesity, a common feature in this X/Y polysomy. The physiopathology of abdominal obesity in the 48,XXYY syndrome is unknown.

Endocrine assays in our patient showed normal pituitary function in spite of hypergonadotrophic hypogonadism. The endocrine findings suggest dysfunction of the Leydig as well as the Sertoli cells, probably explained by the lengthy duration of the disorder. Other adult cases will be required to confirm these anomalies since very few accurate endocrine studies on the 48,XXYY syndrome have been published so far. We make a literature review.

Borgaonkar et al. reviewed the published data on the height of the 53 patients and they concluded that 48,XXYY boys are taller from an earlier age, compared to the general population. Our patient reached only his genetic target height and GH level was normal. Bertelloni et al. reported a central precocious puberty in the 48,XXYY syndrome. We have no indication of this pathology in our case.