Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (97 page)

5.  Trender-Gerhard I, Sweeney MG, Schwingenschuh P, et al. Autosomal-dominant GTPCH1- deficient DRD: clinical characteristics and long-term outcome of 34 patients.
J Neurol Neurosurg Psychiatry.
2009;80:839.

6.  Segawa M, Nomura Y, Nishiyama N. Autosomal dominant guanosine triphosphate cyclohydrolase I deficiency (Segawa disease).
Ann Neurol.
2003;54 (Suppl 6):S32.

TOURETTE SYNDROME

   Definition

Tourette syndrome (TS) is an inherited neuropsychiatric disorder of unknown etiology resulting in motor and phonic tics with an onset in childhood.

   Clinical Presentation

Patients present with sudden, repetitive movements and sounds. The disorder may be chronic or transient. It has a genetic component that is complex and has been associated with a mutation in the gene SLITRK1 on chromosome 13.
¹
This gene appears to be involved in dendritic growth. Patients with TS also frequently have comorbid conditions including attention deficit disorder, obsessive–compulsive disorder, obsessive–compulsive behavior, learning disorders, and oppositional defiant disorder.
²

   Laboratory Findings

The diagnosis of TS is predominantly made on the clinical examination and history. Neuroimaging is not helpful. No laboratory tests are available for the positive diagnosis of TS; however, drug testing to rule out secondary tics should be performed especially for cocaine and dopamine receptor blocking agents. Review of a blood smear may rule out neuroacanthocytosis, which has been associated with tics.

References

1.  Abelson JF, Kwan KY, O’Roak BJ, et al. Sequence variants in SLITRK1 are associated with Tourette’s syndrome.
Science.
2005;310:317.

2.  Freeman RD, Fast DK, Burd L, et al. An international perspective on Tourette syndrome: selected findings from 3,500 individuals in 22 countries.
Dev Med Child Neurol.
2000;42:436.

CEREBRAL PALSY

   Definition

Cerebral palsy is a nonprogressive dysfunction of the cerebral motor regions resulting from perinatal jaundice or asphyxia.
¹

   Clinical Presentation

Patients present in childhood with chorea and muscle tone abnormalities, abnormal reflexes, and coordination. The diagnosis is made primarily based on history and physical findings.

   Laboratory Findings

Testing that may help to rule out alternative causes such as abnormal development of the brain and infarcts includes MRI, cranial ultrasound, and CT scan. EEG may also be used to rule out seizure. Laboratory testing with PT, PTT, Protein C and S, and antithrombin may rule out coagulopathy as a basis for stroke that may mimic cerebral palsy.

Reference

1.  Kuban KC, Leviton A. Cerebral palsy.
N Engl J Med.
1994;330:188.

SYDENHAM CHOREA

   Definition

Sydenham chorea is a sequela of acute rheumatic fever.

   Clinical Presentation

Sydenham chorea is the most common acquired form of chorea in childhood. The onset is usually 1–8 months following the infection and may be insidious or abrupt.
¹
The diagnosis is made by clinical evaluation. No specific laboratory testing currently exists although initial testing for streptococcal infection and ASO titers may be helpful.

Reference

1.  Eshel G, Lahat E, Azizi E, et al. Chorea as a manifestation of rheumatic fever—a 30-year survey (1960–1990).
Eur J Pediatr.
1993;152:645.

LESCH-NYHAN SYNDROME

   Definition

Lesch-Nyhan syndrome is an inherited X-linked recessive trait resulting in hyperuricemia.

   Clinical Presentation