The presentation of<unk>  is variable and at this time not entirely clear. As all known cases were diagnosed postnatally (after birth), and the similar<unk>  is known to have a milder phenotype in prenatally than postnatally diagnosed cases, it is suspected that many cases of<unk>  may be mild or asymptomatic. The intellectual abilities of known XYYY cases have varied, especially in cases with mosaicism, but in most cases are in the borderline intellectual functioning range. Performance IQ is often higher than verbal IQ. Mild speech delays have been reported. Basic self-care skills, such as toileting, dressing, eating, and hygiene, are normal or at most slightly delayed. A number of minor skeletal anomalies are observed, such as clinodactyly, radioulnar synostosis (the fusion of the long bones in the forearm), and poor dental development. These findings are also observed in other sex chromosome aneuploidies. Height is normal to tall, with some cases of abnormally tall stature. Aside from severe acne in adolescence,<unk>  is not associated with any obvious physical or facial abnormalities. Clinodactyly of the right hand As very few cases of<unk>  in adult men have been reported, drawing certain conclusions about sexual functioning and reproduction is difficult. However, low testosterone appears to be associated. All adult men with a non-mosaic 48,XYYY karyotype known to the medical literature have been azoospermic, though one man reported with a 46,XY/48,XYYY mosaic complement (81.1% 48,XYYY) had some evidence of spermatogenesis. Some adults have had impulsive or aggressive sexual behaviour, while some have had low sex drives and no apparent sexual interest; one had gender dysphoria. Two men with<unk>  are known to have had independent adult lives, marrying and finding employment, and only came to medical attention for infertility. Behavioural issues, varying in severity, are associated with the syndrome. Some patients have been transferred to special schools, high-security group homes, or institutions due to severe aggression. However, those cases with particularly severe behavioural issues have generally been from problematic or abusive familial backgrounds. While some descriptions of the syndrome emphasize aggression as a characteristic, the majority of parent reports from a leading chromosome disorder charity emphasize insecurity, immaturity, and shyness. Though teenage boys with<unk>  may be at-risk adolescents, they are capable of positive identity formation, and case reports following the identity formation and personal development of XYYY adolescents have demonstrated a desire to have healthy relationships and integrate successfully into society.
XYYY syndrome
XYYYY syndrome
XYY syndrome
XXYY syndrome
XX male syndrome
XXXY syndrome
Turner syndrome
Klinefelter syndrome