When One Twin Has Turner Syndrome

"What is Turner syndrome? Dr. Henry Turner first discovered Turner syndrome in 1938 (Turner Syndrome Foundation, 2024). This condition occurs only in females and is identified by a chromosomal constitution of 45, XO. Typical females have two X chromosomes as indicated by a chromosomal constitution of 46, XX. In the case of Turner syndrome, it seems that one X chromosome is lost very early in the reproductive process."

"If, for example, an egg loses one X chromosome and is fertilized by a healthy sperm, the result is XO. It is also possible that a sperm might lose an X chromosome or a Y chromosome-if that sperm fertilizes a healthy egg, then the result would be the same. However, due to the mysteries of reproduction and cell division, a female diagnosed with Turner syndrome might have some cells with the typical XX makeup and some cells with XO, a situation known as mosaicism."

"It is recognized as the second most common genetic disorder, estimated to affect between 1/2,000 and 1/2,500 females. In fact, the condition may occur more frequently because the symptoms and severity vary widely, such that some cases of Turner syndrome may be misdiagnosed or even undetected (Sharma & Kitter, 2025). The symptoms vary and can include short stature, ear infections, osteoporosis, diabetes, infertility, and problems with the heart and kidneys."

Turner syndrome is a chromosomal condition occurring only in females characterized by a 45,X karyotype or mosaicism with some cells 46,XX. Loss of an X chromosome can occur in an egg or sperm early in reproduction, producing XO, and mosaicism can result in mixed cell populations. The condition is estimated to affect 1/2,000–1/2,500 females but may be underdiagnosed due to variable severity. Common features include short stature, recurrent ear infections, osteoporosis, diabetes, infertility, and congenital heart and kidney problems. Certain cognitive, emotional, and social difficulties occur, notably impaired visual-spatial skills alongside preserved verbal abilities.

Read at Psychology Today