XXXY Syndrome is an intersex genetic variation where AMAB individuals have two extra X chromosomes. It is estimated that XXXY syndrome affects one in every 50,000 CTM births. It is similar to Klinefelter Syndrome, though the symptoms are usually more severe.[1]
There is a wide variety of symptoms associated with this syndrome. Physical symptoms may include an increased distance between the eyes, an abnormally bent pinkie finger, short nail beds, flat feet, prominent elbows and arms that rest closer to the body, among others. They may experience developmental delays in childhood, as well as other cognitive and behavioral problems, classifying them as neurodivergent. These symptoms are likely to be more severe than someone with Klinefelter syndrome, as it's believed that neurological effects are more severe as the number of extra X chromosomes increases.[2][3]
Those with this variation usually also have hypogonadism, and they usually experience an inability or decreased ability to produce sperm. Many with this syndrome get HRT/testosterone injections in order to go through a more proper or an easier puberty.
It is important to note that not all the symptoms listed in this page are guaranteed to occur in someone with this variation, as someone may only experience one or several of these symptoms, yet still hold the variation.