Leukodystrophy, Hypomyelinating, 13
Patient Information
Characteristics
Background and History
This condition is a severe hereditary developmental disorder of the brain and nervous system. It has so far been reported in 6 members of 3 unrelated families of Ashkenazi Jewish descent.
Clinical Correlations
Children may appear physically normal at birth but from the start have feeding difficulties and generally have poor physical and mental growth. Feeding tube placement may be required for nutrition. Infants may never achieve the usual childhood milestones although there is considerable variability in clinical signs and some children may learn to stand and walk and even say some words. Children seem to be more irritable than normal and their muscles are stiff (spasticity) with hyperactive reflexes. Brain imaging reveals anomalies although these are nonspecific. Poorly defined heart disease is often present and may play a role in the sudden death following a short febrile illness that has been reported in 3 individuals.
In one family of 3 sibs with this condition the optic nerves were pale (optic atrophy) as well as abnormal eye movements (nystagmus) and poor vision.
Genetics
Inheritance
This is an autosomal recessive condition in which both members of a specific pair of genes are changed (mutated). Parents who have one copy are clinically normal but when both carry the mutated gene they confer a 25% risk to each of their offspring to develop this disorder.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
Diagnosis and Prognosis
Pediatricians and neurologists are likely to collaborate on the diagnosis and care of these patients. No treatment is available and considerable supportive care is required. Three of the six patients died before the age of 15 years.
Printer Friendly Version: Ctrl/Cmd+P