Manitoba Oculotrichoanal Syndrome
Patient Information
Characteristics
Background and History
This is a rare familial disorder with most reported cases found in an isolated Manitoba Indian population. Many of the clinical features have not been completely described due to the limited number of patients available.
Clinical Correlations
There is often a notch in the upper eyelids and the eyes appear abnormally far apart. The tear drainage duct is often blocked. One patient had an abnormally small eye (appeared to be absent) and another had a cloudy cornea. The anterior scalp hairline is often abnormally low, sometimes extending to the eyebrow. The tip of the nose is broad and often has a groove. The anus may be closed or abnormally placed.
Genetics
Inheritance
The genetics of this disorder has not been fully described and no responsible mutation has been identified. It is assumed to be inherited in autosomal recessive fashion because of the isolated population in which it has been found. In addition, both sexes are affected and no parent to offspring transmission has been noted.
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 most likely made by pediatricians and ophthalmologists. No information is available on longevity or treatment.
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