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Fraser syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Fraser syndrome

Fraser syndrome is a rare, potentially fatal developmental disorder characterized by eye malformations, fused digits, and genitourinary abnormalities.

Overview

Fraser syndrome affects development before birth. The most characteristic feature is cryptophthalmos, where the eyes are completely covered by skin and often malformed. The severity of the syndrome varies; while it can be fatal before or shortly after birth, some individuals survive into childhood or adulthood.

Symptoms

  • Eyes: Cryptophthalmos (eyes covered by skin), microphthalmia (small eyes), or anophthalmia (missing eyes), leading to vision impairment or loss.
  • Hands and Feet: Cutaneous syndactyly (fusion of skin between fingers and toes).
  • Genitourinary: Renal agenesis (absence of one or both kidneys), bladder abnormalities, and genital anomalies (e.g., undescended testes or ambiguous genitalia).
  • Other: Heart malformations, respiratory tract abnormalities, and facial features such as cleft lip or palate.

Causes

Mutations in the FRAS1, FREM2, or GRIP1 genes cause Fraser syndrome. These genes produce proteins that form the FRAS/FREM complex, which is found in basement membranes that support tissues. This complex acts as an anchor for the top layer of skin. When the complex is absent, the top layer of skin detaches during development, causing blisters that impair the formation of structures like the eyes and digits. The exact mechanism by which this leads to kidney and genital abnormalities remains unclear.

Inheritance

Fraser syndrome is inherited in an autosomal recessive pattern, meaning both copies of the gene in each cell must have mutations. Parents of an affected individual are typically carriers who do not exhibit signs or symptoms of the condition.

Frequently Asked Questions

Ultrasound screening at 18–22 weeks can reveal characteristic features such as absent or malformed eyes, fused digits, and renal agenesis. If these findings are noted, targeted genetic testing via chorionic villus sampling or amniocentesis can assess for pathogenic variants in FRAS1, FREM2, or GRIP1. A detailed family history and carrier testing of parents are also recommended. How is cryptophthalmos managed after birth, and what are the surgical options?::Cryptophthalmos often requires staged surgical procedures. Initial steps may include removal of the skin covering the eye (epithelial debridement) and placement of a temporary ocular prosthesis. Later, definitive surgery may involve creating a functional eyelid and, if possible, reconstructing a corneal surface. Ophthalmology and plastic surgery teams collaborate to optimize visual potential and cosmetic outcomes. What are the risks and management strategies for kidney agenesis in Fraser syndrome?::Renal agenesis can lead to oligohydramnios, pulmonary hypoplasia, and postnatal renal insufficiency. If one kidney is absent, the remaining kidney often compensates, but close monitoring of blood pressure, proteinuria, and renal function is essential. Early nephrology referral, blood pressure control, and avoidance of nephrotoxic medications help preserve kidney health. How does Fraser syndrome affect reproductive planning for parents who are carriers?::Because Fraser syndrome is autosomal recessive, each pregnancy has a 25% chance of being affected if both parents carry a mutation. Genetic counseling can discuss options such as preimplantation genetic testing for monogenic disorders (PGT‑M), prenatal diagnosis, or the use of donor gametes. Discussing family planning early allows parents to make informed decisions.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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