Homocystinuria Due to MTHFR Deficiency (MTHFR)

Homocystinuria is an autosomal recessive disorder caused by pathogenic variants in multiple genes, including MTHFR. This gene encodes an enzyme (methylenetetrahydrofolate reductase) which helps catalyzes the conversion of homocysteine to methionine. Pathogenic variants in MTHFR reduce enzymatic activity, leading to a buildup of homocysteine in the blood. The onset of homocystinuria due to MTHFR deficiency occurs within the first year of life or later in childhood and adulthood. The clinical presentation includes developmental delay, intellectual disability, short stature, hypotonia, blood vessel disease, and seizures. Life expectancy depends on severity of symptoms but can be reduced.

For information about carrier frequency and residual risk, please see the residual risk table.

This gene is included on the following panel(s):