Trisomy X (Triple XXX Syndrome)

In this variation, a person is born with 47XXX chromosomes instead of the typical 46XX. If the additional X chromosome comes from the parents’ original sperm or egg cell, all of their cells will have 47XXX chromosomes. If the additional chromosome appears early during the embryo’s development, only some cells will have 47XXX chromosomes, resulting in a mosaic chromosome pattern (e.g., 46XX/47XXX or 45X/47XXX). Most people with 47XXX chromosomes do not develop any variations in their other sex characteristics, but some may have ovaries that stop producing hormones at an earlier-than-typical age, and some may not menstruate.

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