<unk> , also known as de la Chapelle syndrome, is a rare congenital intersex condition in which an individual with a 46, XX karyotype (otherwise associated with females) has phenotypically<unk>  characteristics that can vary among cases. Synonyms include 46,XX testicular difference of sex development (46,XX DSD), 46,XX sex reversal, nonsyndromic 46,XX testicular DSD, and XX sex reversal. In 90 percent of these individuals, the syndrome is caused by the Y chromosome's SRY gene, which triggers<unk>  reproductive development, being atypically included in the crossing over of genetic information that takes place between the pseudoautosomal regions of the X and Y chromosomes during meiosis in the father. When the X with the SRY gene combines with a normal X from the mother during fertilization, the result is an XX<unk> . Less common are SRY-negative XX<unk> s, which can be caused by a mutation in an autosomal or X chromosomal gene. The masculinization of XX<unk> s is variable. This syndrome is diagnosed through various detection methods and occurs in approximately 1:20,000 newborn<unk> s, making it much less common than Klinefelter syndrome. Treatment is medically unnecessary, although some individuals choose to undergo treatments to make them appear more<unk>  or female. The alternative name for<unk>  refers to Finnish scientist Albert de la Chapelle, who studied the condition and its etiology.
XX male syndrome
XYY syndrome
XXXY syndrome
XYYY syndrome
XXYY syndrome
XXXXY syndrome
Turner syndrome
XYYYY syndrome