Practice question

Turner syndrome monosomy X karyotype 45,X found in about 1 in 2500 female births though 99 percent concepti abort spontaneously, indicating strong selection. Phenotype includes short stature below third centile under 150 cm, primary amenorrhea due to streak ovaries and infertility hypergonadotropic, webbed neck with low hairline, broad chest widely spaced nipples, lymphedema newborn feet hands, coarctation aorta bicuspid valve, renal anomalies horseshoe kidney, normal intelligence usually with specific visuospatial learning difficulties. Single X random loss paternal or maternal sex chromosome through nondisjunction generating nullisomic gamete fertilized by X-bearing gamete.