Heimler Syndrome 1
Patient Information
Characteristics
Background and History
The first example of this syndrome was reported by A. Heimler in 1991. Several possible variants have been described since (see Heimler Syndrome 2).
Clinical Correlations
The pigmentation of the retina may be abnormal but no data on vision are available.
This is a rare syndrome and only a few patients have been described. Severe hearing loss has been diagnosed in the first year or two of life. Primary teeth seem to be normal but secondary teeth have a deficiency of enamel. The toe nails have abnormal ridges while the fingernails have white spots.
General development and mental functioning seem to be normal.
Genetics
Inheritance
Changes in the DNA (mutations) have been found in both members of a specific gene. The parents are normal but presumably carry one mutated copy so there is a 25% chance that each child will inherit both copies and have this syndrome. The transmission pattern of Heimler Syndrome 1 is autosomal recessive.
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 is unlikely to be made at birth based on the physical findings. The presence of hearing loss within the first two years is obviously not diagnostic but combined with the abnormal secondary teeth when present in young children should arouse suspicion. The abnormal toe and fingernails could be helpful but the age of onset of these signs is unknown.
Gene studies are necessary to make the diagnosis.
Longevity is unlikely to be impacted.
Nothing is known regarding treatment of the general disorder but assistive hearing devices could be helpful.
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