Counselling of a couple faced with a prenatal diagnosis of Klinefelter syndrome.

UNLABELLED: When a prenatal diagnosis of Klinefelter syndrome (KS) is made, a couple is faced with an unfamiliar and unexpected diagnosis. The aim of this article is to give clues to prenatal counselling in this situation. The information provided to couples facing a prenatal diagnosis of KS should ideally be based on longitudinal studies of unselected individuals, including those diagnosed prenatally. Indeed, there are several reasons to think that the phenotype of individuals diagnosed prenatally is globally less severe than in those diagnosed postnatally. Based on these studies, the evidence to be explained to couples to help them make an informed decision about the pregnancy is the following: except for rather tall height, generally normal appearance throughout life; increased risk of learning disabilities; spontaneous puberty, reduced testicular size, usual need for testosterone supplementation from adolescence onward; increased risk of gynecomastia; sexual orientation similar to the general male population; infertility, but with the possibility of having biological offspring with assisted reproductive techniques. In this article, we review the evidence about the phenotype of KS according to the circumstances of diagnosis and its use in counselling couples faced with a prenatal diagnosis of this common condition. CONCLUSION: Cohort studies including individuals with KS diagnosed prenatally are still lacking.

Comparison of adolescents with Klinefelter syndrome according to the circumstances of diagnosis: amniocentesis versus clinical signs.

AIMS: We compared the phenotype of adolescents with Klinefelter syndrome diagnosed by amniocentesis or postnatally to the general population with a view to evidence-based genetic counselling. METHODS: The charts of 28 patients seen between ages 12 and 18 years were reviewed. Physical and neurodevelopmental data were compared between patients diagnosed by chance (amniocentesis, group A, n = 11) or on the basis of symptoms (group B, n = 17) and the general population. Our hypothesis was that group A would have a more heterogeneous and less severe phenotype than group B. RESULTS: All patients had spontaneous puberty. The 2 patient groups were similar in physical development. Mean testosteronemia became lower than the normal mean from age 14 years. Compared to the general population, the prevalence of gynecomastia and school delay in group A was not significantly different (gynecomastia 33 vs. 40%, p = 0.70; school delay 40 vs. 20%, p = 0.25). In contrast, gynecomastia (77%) and school delay (56%) were significantly more frequent in group B than in the general population (p = 0.01 for both). CONCLUSIONS: Although they are based on a small number of patients, our data provide the groundwork for cautious optimism in prenatal counselling for Klinefelter syndrome.