Fraser Syndrome 2
Patient Information
Characteristics
Background and History
This is a rare hereditary disorder that primarily involves the eyes, the eyelids, the reproductive system, and the urinary tract.
Clinical Correlations
The eyelids are fused and often cannot be opened. The eyeball behind the lids may be severely malformed and often nonfunctional. The nose is often malformed or underdeveloped. The digits (fingers and toes) may not be completely separated with persistent webbing of the skin between them. A variety of genitourinary anomalies have been described such as an absent bladder, malformed or absent kidneys, pulmonary dysfunction, and ambiguous genitalia, both internal and external.
Genetics
Inheritance
This is an autosomal recessive condition caused by mutations in both members of a specific gene. Parents, who are clinically normal, may carry a single mutation in one member of the pair but each offspring of two such parents has a 25% risk of Fraser syndrome 2.
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 presence of fused eyelids (in one or both eyes) at birth is an important sign and the presence of other malformations described here can be diagnostic. DNA testing is useful to distinguish this disorder from similar ones. Pediatricians and ophthalmologists are likely to collaborate on this condition.
Only a few families have been reported in the medical literature. Depending upon the severity of the malformations some infants may not survive beyond the newborn period.
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