Fraser syndrome (FS), also known as cryptophthalmos-syndactyly syndrome, is a rare autosomal recessive condition affecting approximately 1 in 200 000 newborns. FS arises from mutations in the FRAS1 (approximately 50% of cases), FREM1, FREM2, or GRIP1 genes, which cause failure of apoptotic processes during embryogenesis and defects in connective tissue development. The condition affects males and females equally. It is reportedly more prevalent in the Roma populations of southern and eastern Europe.

FS is characterized by unilateral or bilateral cryptophthalmos (skin covering the eyes), with or without underlying abnormalities of the eye; syndactyly (fused digits of the hands and feet); renal agenesis; and genital anomalies such as cryptorchidism and ambiguous genitalia. Less common abnormalities include heart malformations, anomalies of the larynx and respiratory tract, and cleft lip / palate. The condition can be fatal in the antenatal and neonatal periods, but individuals with lower severity of symptoms can live into childhood or adulthood with a normal life expectancy.

The prognosis depends on the severity of the condition. Death within the first year of life is common in affected newborns with severe anomalies.