It is characterized by developmental defects including cryptophthalmos (where the eyelids fail to separate in each eye), and intersex development in the genitals (such as micropenis or clitoromegaly) and cryptorchidism.

[10] In 6 of 18 consanguineous families with Fraser syndrome, van Haelst et al. (2008) excluded linkage to both the FRAS1 and FREM2 genes, indicating genetic heterogeneity.

[citation needed] In 5 families with Fraser syndrome, McGregor et al. (2003) identified 5 homozygous mutations in the FRAS1 gene (e.g., 607830.0001), which encodes a putative extracellular matrix (ECM) protein.

[8] In an infant girl with Fraser syndrome, Slavotinek et al. (2006) identified compound heterozygosity for a deletion (607830.0006) and an insertion (607830.0007) in the FRAS1 gene, inherited from her mother and her father, respectively.

Cavalcanti et al. (2007) concluded that a phenotype resembling AMS is a rare clinical expression of Fraser syndrome, with no obvious genotype/phenotype correlation.

An earlier pregnancy had resulted in the intrauterine death at 30 weeks of gestation of a male fetus with a normal karyotype in whom the diagnosis of Fraser syndrome was suggested by the presence of cryptophthalmos, syndactyly, ambiguous genitalia, imperforate anus, bilateral renal agenesis, pulmonary hypoplasia, and hydrocephalus.

Minor criteria were congenital malformation of the nose, ears, or larynx, cleft lip and/or palate, skeletal defects, umbilical hernia, renal agenesis, and intellectual disability.

[citation needed] Boyd et al. (1988) suggested that prenatal diagnosis by ultrasound examination of eyes, digits, and kidneys should detect the severe form of the syndrome.

Major criteria included syndactyly, cryptophthalmos spectrum, urinary tract abnormalities, ambiguous genitalia, laryngeal and tracheal anomalies, and positive family history.