Jacobs Syndrome

Excerpt

Jacobs syndrome, also known as 47,XYY syndrome, is a rare genetic condition that occurs in about 1 out of 1000 male children; this condition belongs to a group of conditions known as "sex chromosome trisomies", with Klinefelter syndrome being the more common type. This condition was initially discovered in the 1960s. Early studies performed on institutionalized men found that 47,XYY males were more likely to exhibit antisocial tendencies than those without this genotype. The median age of diagnosis is approximately 17 years, with many patients presenting due to infertility concerns. Patient presentations may vary greatly, and in fact, many patients have relatively few, if any, phenotypic abnormalities. Those who do, however, may display macroorchidism, tall stature, macrocephaly (abnormally large head), and hypertelorism (increased distance between two body parts, typically the eyes), among other features. These patients are also more likely than the general population to be diagnosed with asthma, autism spectrum disorder, and seizures. While some 47,XYY individuals are infertile, those who are able to reproduce often produce offspring that have normal karyotypes.