Psychiatric symptoms and CK-Elevation as initial manifestations of late-onset Tay-Sachs disease

Medical History: In a 15 year old boy who was treated in the Department of Child Psychiatry due to a bipolar disorder a routine blood check revealed a CK-Elevation of 1100U/l. The medical treatment of the psychiatric disease was difficult. The patient reported muscular cramps that appear especially while distension and sometimes while physical training and some difficulties in climbing steps. Clinical examination showed muscle contractions after percussion, but no other signs of myotonia. There was mild proximal weakness with a postive Gowers sign.