OMIM ID:
Fraser Syndrome 1
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Cryptophthalmos is the major ocular malformation in Fraser syndrome but is a feature in only 93% of patients. The globe is often small and sometimes completely absent or in some cases consisting of only rudimentary ocular tissue. The cornea is often adherent to the eyelid tissue. The lacrimal ducts may be deformed or absent and the lids are often fused.
Systemic Features
The most common malformations seen in this disorder are syndactyly (61.5%), cryptophthalmos (88%), and genitourinary malformations but others of a great variety have also been reported, such as laryngeal stenosis, deafness, and deformities of the nares and external auditory meati. Ambiguous genitalia occur in 17%. Some infants are stillborn and many do not survive the neonatal period. Cognitive deficits and congenital heart disease are common.
Genetics
Inheritance
Fraser syndrome 1 is caused by homozygous or heterozygous mutations in the FRAS1 gene (4q21.21).
Fraser syndrome 2 (617666) results from homozygous mutations in the FREM2 gene (13q13.3). Parental consanguinity is common (25%) and familial patterns are consistent with autosomal recessive inheritance.
Fraser syndrome 3 (617667) results from homozygous mutations in the GRIP1 gene (12q14.3). Three consanguineous families have been reported.
Mutations in GRIP1 (PAD14) (12q14.3) have also been found in 3 families in which the parents were consanguineous.
Isolated cryptophthalmos (123570) also occurs in autosomal dominant pedigrees as well as sporadically. It is rarely found as an incidental feature of other syndromes.
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.