Fraser syndrome
Encyclopedia
Fraser syndrome is an autosomal recessive
congenital disorder
. The syndrome is named after George Fraser
.
(where the eyelids fail to separate in each eye), and malformations in the genitals (such as micropenis
, cryptorchidism
or clitoromegaly
). Congenital malformations of the nose
, ear
s, larynx
and renal system, as well as mental retardation
, manifest occasionally. Syndactyly
(fused fingers or toes) has also been noted in some cases.
The genetic background of this disease has been linked to a gene called FRAS1
, which seems to be involved in skin epithelial morphogenesis
during early development. It has also been associated with FREM2
.
.
Recessive
In genetics, the term "recessive gene" refers to an allele that causes a phenotype that is only seen in a homozygous genotype and never in a heterozygous genotype. Every person has two copies of every gene on autosomal chromosomes, one from mother and one from father...
congenital disorder
Congenital disorder
A congenital disorder, or congenital disease, is a condition existing at birth and often before birth, or that develops during the first month of life , regardless of causation...
. The syndrome is named after George Fraser
George R. Fraser
George R. Fraser is a medical geneticist.In 1962, he characterized the condition later known as Fraser syndrome.-References:...
.
Signs and symptoms
It is characterized by developmental defects including cryptophthalmosCryptophthalmos
Cryptophthalmos is a rare congenital anomaly in which the skin is continuous over the eyeball with absence of eyelids. It is classified into three types: complete, incomplete and abortive. Failure of eyelid separation can be associated with maldevelopment of the underlying cornea and microphthalmia...
(where the eyelids fail to separate in each eye), and malformations in the genitals (such as micropenis
Micropenis
Micropenis is an unusually small penis. A common criterion is a dorsal erect penile length of at least 2.5 standard deviations smaller than the mean human penis size. The condition is usually recognized shortly after birth...
, cryptorchidism
Cryptorchidism
Cryptorchidism is the absence of one or both testes from the scrotum. It is the most common birth defect regarding male genitalia. In unique cases, cryptorchidism can develop later in life, often as late as young adulthood. About 3% of full-term and 30% of premature infant boys are born with at...
or clitoromegaly
Clitoromegaly
Clitoromegaly is an abnormal enlargement of the clitoris ....
). Congenital malformations of the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
, ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
s, larynx
Larynx
The larynx , commonly called the voice box, is an organ in the neck of amphibians, reptiles and mammals involved in breathing, sound production, and protecting the trachea against food aspiration. It manipulates pitch and volume...
and renal system, as well as mental retardation
Mental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
, manifest occasionally. Syndactyly
Syndactyly
Syndactyly is a condition wherein two or more digits are fused together. It occurs normally in some mammals, such as the siamang and kangaroo, but is an unusual condition in humans.-Classification:...
(fused fingers or toes) has also been noted in some cases.
Genetics
FRAS1
Extracellular matrix protein FRAS1 is a protein that in humans is encoded by the FRAS1 gene. This gene encodes an extracellular matrix protein that appears to function in the regulation of epidermal-basement membrane adhesion and organogenesis during development....
, which seems to be involved in skin epithelial morphogenesis
Morphogenesis
Morphogenesis , is the biological process that causes an organism to develop its shape...
during early development. It has also been associated with FREM2
FREM2
FRAS1-related extracellular matrix protein 2 is a protein that in humans is encoded by the FREM2 gene.-Further reading:...
.
Diagnosis
The diagnosis of this syndrome can be made on clinical examination and perinatal autopsyAutopsy
An autopsy—also known as a post-mortem examination, necropsy , autopsia cadaverum, or obduction—is a highly specialized surgical procedure that consists of a thorough examination of a corpse to determine the cause and manner of death and to evaluate any disease or injury that may be present...
.