Strong Genetic

Fanconi Anemia Group C

Name: Fanconi Anemia Group C
Creator: Realised
Published: 2026-03-01

GeneFANCCrsIDrs104886456, rs104886457, rs104886458InheritanceAutosomal recessiveCarrier frequency~1 in 89 Ashkenazi Jewish, rare in general populationSystemCarrier Screening

Summary

Fanconi anemia is a DNA repair disorder — the FANCC gene is part of a pathway that fixes a specific type of DNA damage called interstrand crosslinks. When this repair system fails, cells accumulate DNA damage at an accelerated rate, affecting blood cell production and dramatically increasing cancer risk.

Practical takeaway

This matters when planning children. If your partner is also of Ashkenazi Jewish descent, carrier testing is particularly relevant — the IVS4+4A>T variant has a carrier frequency of approximately 1 in 89 in this population. A carrier test through a GP or genetic counselling service can determine your partner's status. A genetic counsellor can also discuss the broader Fanconi anemia gene panel, since variants in other FA pathway genes would also result in an affected child if combined with your FANCC variant. Realised does not calculate reproductive risk or advise on reproductive decisions.

Evidence detail

What Carrier Status Means For You

You are not affected. Carriers of a single FANCC variant have completely normal blood counts, normal DNA repair capacity for practical purposes, and no increased cancer risk. Your carrier status becomes relevant if your partner also carries a variant in a Fanconi anemia gene (there are 22+ FA genes, though FANCC is the most common in the Ashkenazi population). If both parents carry a variant in the same FA gene, each child has a 25% chance of being affected, a 50% chance of being a carrier, and a 25% chance of inheriting neither variant.

Population Context

The IVS4+4A>T variant is an Ashkenazi Jewish founder mutation and accounts for the majority of FANCC cases in this population. Fanconi anemia Group C is one of the most common FA subtypes worldwide, though FA overall is rare (approximately 1 in 130,000 births). Other FANCC variants occur in diverse populations at much lower frequencies. Fanconi anemia is part of the standard Ashkenazi Jewish carrier panel. The condition is named after Swiss paediatrician Guido Fanconi, who described it in 1927.

Limitations

23andMe tests 3 FANCC variants. For Ashkenazi Jewish individuals, the IVS4+4A>T variant provides good coverage of the most common disease allele. However, Fanconi anemia can be caused by variants in 22+ different genes — a negative FANCC result does not rule out carrier status for other FA genes. Comprehensive Fanconi anemia carrier screening through a clinical laboratory covers multiple FA genes and provides broader sensitivity. A "not detected" result for FANCC reduces but does not eliminate FA carrier risk overall.

Sources (5)

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