New-onset Tourette syndrome following human growth hormone therapy.

tion tests, and urine analysis were normal. There were no factors causing short stature such as chronic illness, primary bone disease or a dysmorphic syndrome. Maximal plasma GH response to standard stimulation tests with clonidine and insulin was ! 10 ng/ml. Magnetic resonance imaging (MRI) of hypophysis was normal. The patient was diagnosed as having idiopathic growth hormone deficiency (GHD) and recombinant hGH at 0.03 mg/kg/day was started. He was followed up at 3-monthly intervals. Two years later, the height velocity of the patient increased from 3 cm/year to 8 cm/year. Physical and neurological examinations including optic disc and retina were normal except for motor and vocal tics such as throat-clearing sounds, shoulder shrug, and facial grimace. A detailed history revealed that tics developed approximately 6 months after hGH therapy was started. Shoulder shrug and facial grimace started almost at the same time and became increasingly severe. Eight months later, throat-clearing sounds became apparent. Motor and vocal tics occurred nearly every day but they decreased markedly during sleep. At that time, the psychiatric evaluation was normal. Laboratory studies including complete blood count, serum glucose, electrolytes, renal and liver function tests, lipid profile, thyroid function tests, prolactin, ceruloplasmin, antistreptolysin O antibody, and urinary copDear Sir, Tics are described as spontaneous, brief, quick, sudden, recurrent, repetitive, purposeless, and stereotyped movements or noises [1] . Tic disorders are classified as (1) transient tic disorder, (2) chronic motor or chronic vocal tic disorder and (3) Tourette syndrome (TS). Of these, TS is the most severe form presenting with both multiple motor and one or more vocal tics and usually starting in childhood [1] . The use of human growth hormone (hGH) in children and adolescents is generally safe. However, it may cause some side effects in a minority of cases [2, 3] . There is no record of tic disorders being associated with hGH therapy. In this paper, a patient with TS whose motor and vocal tics developed during hGH therapy is presented.