XXYYY syndrome

Not to be confused with XXXYY syndrome, XYYYY syndrome, XXYY syndrome, or XYYY syndrome.

49,XXYYY syndrome is an intersex variation in which a person has two extra Y chromosomes and one extra X chromosome. It is a very rare variation among males and there is no rarity estimate. This medical condition is recorded since the 1960s.

XXYYY Syndrome
Specialty	Medical genetics
Diagnostic method	Karyotype

People with this genetic variation tend to present with facial dysmorphism, mild microcephaly, limited supination at the elbows, delayed bone age, and moderate intellectual disability. This variation is often considered a subset of Klinefelter syndrome. If these symptoms cause physical difficulties, they may be classified as a physical disability.

Medical professionals analyzed tissue samples taken for chromosomal studies from ambiguous external genitalia and abdominal gonads, consisting of a left ovotestis and a right primitive testis, and found that they contained cells with sex chromosomes 46,XX, 47,XXY, and 49,XXYYY. This implies that those with ambiguous genitalia or ovotesticular tissue may, in some cases, have the genetic material to generate, raise, or develop a child with 49,XXYYY syndrome, if they are able to ovulate and/or produce sperm.

The 49,XXYYY syndrome, as a rare sex chromosomal aneuploidy (SCA), is often studied such as together with 45,X, known as Turner syndrome, 47,XYY, known as Superman or Jacobs syndrome, 47,XXX, known as trisomy X, 48,XYYY, 48,XXYY, mosaicism 46,XY/47,XYY, 48,XXYY, 49,XXXYY, 48,XXXX, known as tetrasomy X, and 49,XXXXX, known as pentasomy X. These medical conditions are considered intersex variations.