A male with the 47 XYY syndrome may have a number of clinical findings. Many patients may go undiagnosed.


Common clinical findings include:

(1) tall stature

(2) macrocephaly

(3) macro-orchidism starting with puberty

(4) hypotonia

(5) hypertelorism

(6) tremor


Additonal findings may include:

(1) autism spectrum disorder

(2) macrodontia and/or prognathic jaw

(3) pes planus

(4) central adiposity

(5) clinodactyly

(6) seizures

(7) asthma


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