What is Triple X Syndrome? Also known as Trisomy X or 47,XXX , this is a genetic condition that uniquely affects females, occurring in about 1 in every 1,000 female births. Females typically inherit two X chromosomes (XX)—one from each parent. In Triple X syndrome, a female is born with three X chromosomes (XXX). Key Insight: Because the body naturally inactivates the extra X chromosomes in each cell, many girls and women with this condition have absolutely no symptoms or very mild ones. The vast majority lead full, completely normal lives. Symptoms Symptoms vary drastically from person to person. Some girls are never clinically diagnosed because their symptoms are so mild. If symptoms are noticeable, they generally fall into three categories: 1. Physical Traits Tall Stature: Often noticeably taller than average compared to the rest of their family, usually with disproportionately long legs. ...