XYY syndrome
XYY syndrome is a sex chromosomal syndrome syndrome with 47 chromosomes, not 46 chromosomes in general, with one male Y chromosome. Jacob syndrome, also known as Jacobs syndrome. This syndrome produces 47, XYY karyotypes, which occur in one out of 1,000 live births. Since the medical phenotype is normal and the majority of 47, XYY males do not know their karyotype, there is controversy as to whether it is appropriate to call this term syndrome among some medical geneticists.