The retina and optic nerve developmentally are outgrowths of the brain and therefore consists of neurological tissue. It is not surprising therefore that hereditary disorders of the brain are associated with diseases of the retina as in the case of the condition described here.
Degeneration of the retina and optic nerve may be suspected soon after birth. Infants that at birth seemed to see using eye movements to follow targets may lose that ability later during the neonatal period. Eye movements become random (nystagmus). Degeneration of the optic nerve (optic atrophy) has been diagnosed by three months of age and testing for rod and cone (cells called photoreceptors) responses to light suggest that they are no longer functioning.
Infants generally appear normal at birth but within a few months it becomes apparent that they are not developing normally. They do not achieve the usual early childhood milestones such as sitting, rolling over, and responding to their environment. Brain imaging reveals that parts of the brain are not growing normally and specifically the cerebellum (important for balance and coordination) is underdeveloped. Physical and mental growth is severely delayed. General debilitation and lack of development can lead to death in the first year of life although some live into the second decade.
This condition follows an autosomal recessive pattern of inheritance as the result of a change (mutation) in both copies of a specific gene. Parents with one copy of the mutation are clinically normal but in families in which both parents are carriers (have a single copy of the mutation), the risk to each of their children for this disorder is 25% to inherit both mutated copies.
The diagnosis is most likely made with a team approach consisting of pediatricians, neurologists, and ophthalmologists. Confirmation of the diagnosis requires gene studies. No treatment other than supportive care is known and the progressive neurological deterioration often leads to death at an early age.