JACOB’SSYNDROME

PRESENTED BY:

YAMSON, A. J .

STEM-11B

DESCRIPTION genetic condition that occurs when a male has

an extra copy of the Y chromosome in each of their cells

Other names:

XYY Syndrome

XYY Karyotype

YY Syndrome

FREQUENCY

1 out of every 1000 boys

5 – 10 boys (United States)

SYMPTOMS

• severe acne in adolescence

• learning disabilities

• delayed motor skill development

• emotional and behavioral difficulties

• hypotonia

• involuntary muscle movements

• taller-than-average height

• larger head dimensions

• low testosterone levels

• infertility

CAUSE

• cell-division error in the sperm prior to conception

known as “nondisjunction”