This is a severe and progressive hereditary neurological condition.
Infants may appear normal at birth but it is soon obvious that neurological development is delayed. The growth of the skull is also delayed after birth leading to microcephaly. Most infants are floppy (hypotonia) and never achieve sitting or standing nor do they learn to speak. The limbs may be stiff and spastic. Seizures often occur beginning in the second year of life. Swallowing may become difficult and feeding tubes are often required. Young children may have respiratory problems.
There is evidence of poor vision and the optic nerves are pale (optic atrophy). The eyes may not have full movement and often infants will not visually follow targets.
This is an autosomal recessive condition caused by changes (mutations) in the DNA of a specific gene. These affect both members of a pair that are contributed by the parents. The clinically normal parents may each contribute one member of the pair thus conferring a 25% risk of this disorder to each child.
A pediatric neurologist or pediatrician is most likely to diagnosis this condition. Among the confirmatory tests that help to diagnose are an EEG, an MRI, and a VEP. The child's feeding status must be monitored to ensure that nutritional intake is adequate. Respiratory hygiene is important as difficulty breathing can be responsible for childhood deaths.