Behr syndrome
Incidence
Behr syndrome is an inherited disorder transmitted in an autosomal recessive pattern. Autosomal recessive cases.
Heterogeneous.The frequency of Behr syndrome is unknown and both sexes are equally affected.
Clinical Characteristics
Onset in early infancy. Mild manifestations in heterozygotes. Behr syndrome includes an optic atrophy associated with neurological manifestations. Visual impairment is moderate to severe and appears early in life. A sensory nystagmus may be observed. The neurological manifestations show an inter- and intra-familial variability: they can include myoclonic epilepsy, progressive spastic paraplegia due to pyramidal tract involvement, dysarthria, extra-pyramidal tract signs, ataxia, urinary incontinence, mental retardation, posterior column sensory loss or muscle contractures (predominant in the lower limbs). These neurological signs manifest progressively during childhood and become prominent in the second decade. By this age, most of the patients with Behr are housebound walkers or nonfunctional walkers. Surgery for the Achilles tendon or the adductor longus is often required. The frequency of Behr syndrome is unknown and both sexes are equally affected. Neuro-imagery reveals atrophy of the cerebellum in some cases and diffuse, symmetric white matter abnormalities. Behr syndrome may therefore represent a pathology of the cerebral white matter, associated with an unknown biochemical abnormality. In some Jewish-Iraqi pedigrees affected with Behr syndrome, urinary testing revealed a 3-methylglutaconic aciduria and a 3-methylglutaric aciduria. However, the relationship between optic atrophy and these enzymatic deficiencies is still unknown. Clinical manifestations of Behr syndrome associated with specific aciduria are similar to those of the form with normal urinary testing, although extra-pyramidal manifestations are encountered earlier and females appear more affected than males in the aciduria-associated form.
Precipitants
none
Provocation Tests
none
Diagnostic Procedures
It is a clinical diagnosis. In some Jewish-Iraqi pedigrees affected with Behr syndrome, urinary testing revealed a 3-methylglutaconic aciduria and a 3-methylglutaric aciduria.