Textual Definition of Jacob's Syndrome
A chromosome abnormality characterized by the presence of an additional Y chromosome, the sex chromosome that determines male gender. Affected individuals are sometimes referred to as "hypermasculine" or "supermales."
It occurs as frequently as one in 840 live male births but may remain undiagnosed throughout life, as the features are subtle. They include accelerated growth in mid-childhood, potentially explosive, antisocial behaviour, relative weakness, poor coordination of fine motor skills and low intelligence; IQ is usually 10 to 15 points below unaffected siblings. Physically, affected individuals tend to be tall and this, with mildly sunken chests (Pectus excavatum). Severe acne may develop in adolescence.
It has been suggested that individuals with this Karyotype are more prone to criminal behavior, but studies have not corroborated this speculation, through among institutionalized male juvenile delinquents, incidence has been reported as much as 24 times above that in the general population.
Affected individuals have passed the condition on to their sons only in very rare instances, though the majority of XYY individuals are fertile.
Textual Definition From:
The Encyclopedia of Genetic Disorders and Birth Defects III Edition. James Wynbrandt, Mark D. Ludman, M.D., F.R.C.P.C. 399.
616.04203. 2008.
CKPL.
It occurs as frequently as one in 840 live male births but may remain undiagnosed throughout life, as the features are subtle. They include accelerated growth in mid-childhood, potentially explosive, antisocial behaviour, relative weakness, poor coordination of fine motor skills and low intelligence; IQ is usually 10 to 15 points below unaffected siblings. Physically, affected individuals tend to be tall and this, with mildly sunken chests (Pectus excavatum). Severe acne may develop in adolescence.
It has been suggested that individuals with this Karyotype are more prone to criminal behavior, but studies have not corroborated this speculation, through among institutionalized male juvenile delinquents, incidence has been reported as much as 24 times above that in the general population.
Affected individuals have passed the condition on to their sons only in very rare instances, though the majority of XYY individuals are fertile.
Textual Definition From:
The Encyclopedia of Genetic Disorders and Birth Defects III Edition. James Wynbrandt, Mark D. Ludman, M.D., F.R.C.P.C. 399.
616.04203. 2008.
CKPL.