Categories : Genetics Endocrinology Paediatrics Gynecology. Learn more about the latest developments in Fertility and IVF. Prenatal testing can also be performed. Stage 3 of Rett syndrome can begin as early as 2 years or as late as 10 years.
Female Sex Chromosome Abnormalities. Researchers are working to determine which genes contribute to the specific developmental and physical differences that can occur with Klinefelter syndrome. As a result, they produce relatively small amounts of testosterone.
Submit Feedback. Most commonly, affected individuals are taller than average are unable to father biological children infertile ; however the signs and symptoms of Klinefelter syndrome vary among boys and men with this condition.
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Variations include:. Fragile X Syndrome. Please send your comments to suggestions siliconpractice. Later on during regression, the child may experience periods of rapid breathing hyperventilation or slow breathing, including breath-holding.