(See also Overview of Chromosomal Anomalies Overview of Chromosomal Anomalies Chromosomal anomalies cause various disorders. Anomalies that affect autosomes (the 22 paired chromosomes that are alike in males and females) are more common than those that affect sex chromosomes... read more and see Overview of Sex Chromosome Anomalies Overview of Sex Chromosome Anomalies Sex chromosome anomalies may involve aneuploidy, partial deletions or duplications of sex chromosomes, or mosaicism. (See also Overview of Chromosomal Anomalies.) Sex chromosome anomalies are... read more .)
The 47,XYY syndrome occurs in about 1/1000 live male births.
Affected boys tend to be taller than average and have a 10- to 15-point IQ reduction compared with family members. There are few physical problems. Minor behavior disorders, hyperactivity, attention-deficit disorder, and learning disorders Overview of Learning Disorders Learning disorders are conditions that cause a discrepancy between potential and actual levels of academic performance as predicted by the person’s intellectual abilities. Learning disorders... read more are more common.