Heimler Syndrome 2
Patient Information
Characteristics
Background and History
This condition was first described by A. Heimler and coworkers in 1991. Few families have been reported since then.
See Heimler Syndrome 1 for a variant with some similar signs.
Clinical Correlations
The primary teeth are apparently normal but secondary teeth have defective enamel (outer coating). Hearing loss of the sensorineural type develops in the first 3 years of life. Vision loss has been noted in a single patient during the 3rd decade and detailed studies revealed changes in the retina. The nails develop ridges and white spots. Psychomotor development seems to be normal.
Genetics
Inheritance
This is a familial disorder caused by a mutation (change in DNA) in both members of a specific gene. The family pattern suggests autosomal recessive inheritance since both sexes are affected and no parent-to-child transmission has been seen. The parents who likely carry a single mutation are clinically normal. Such parents would confer a 25% risk to each of their children to inherit 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
The diagnosis depends upon dental and hearing evaluations as well as examination of the nails and the eye. The prognosis is excellent but low vision and hearing assistance devices should be of benefit.
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