Familial Infantile Bilateral Striatal Necrosis

Familial infantile bilateral striatal necrosis is the familial form of infantile bilateral striatal necrosis (IBSN; see this term), a syndrome of bilateral symmetric spongy degeneration of the caudate nucleaus, putamen and globus pallidus characterized by developmental regression, choreoathetosis and dystonia progressing to spastic quadriparesis.

Epidemiology

The prevalence of familial IBSN has been estimated at less than 1/1,000,000.

Clinical description

The age of onset varies between 7 months and 15 months. Clinical features include choreoathetosis, dystonia, rigidity, spasticity, dysphagia, optic atrophy, intellectual deficit, developmental regression of motor and verbal skills, failure to thrive, myoclonus, quadriparesis, cerebellar ataxia and nystagmus. The disease has an insidious onset and a slowly progressive downhill course.

Etiology

Autosomal recessive infantile striatonigral degeneration is caused by mutation in the NUP62 gene (19q13.33) and mitochondrial infantile striatonigral degeneration is caused by mutation in the ATP synthase-6 gene (MTATP6).

Diagnostic methods

Diagnosis is based on clinical observation of choreoathetoid movements of the face, trunk and extremities and evidence of basal ganglia degeneration on CT and MRI images.

Differential diagnosis

Differential diagnoses include Wilson's disease, acute disseminated encephalomyelitis, neurodegeneration with brain iron accumulation, Leigh disease, juvenile Huntington chorea, methylmalonic aciduria, guanidinoacetate methyltransferase deficiency, glutaric acidemia I (see these terms), carbon monoxide intoxication, small vessel arteritis and trauma.

Genetic counseling

Antenatal diagnosis and genetic counseling is offered to families of affected patients.

Management and treatment

There is no standard therapy for familial IBSN. Treatment with oral biotin has been observed to slow disease progress initially.

Prognosis

Prognosis is usually poor with patients progressing to spastic quadriparesis followed by death, usually due to infection.