Homocystinuria due to MTHFR Deficiency (MTHFR)

Homocystinuria due to MTHFR deficiency is an autosomal recessive disorder caused by pathogenic variants in the gene MTHFR. Patients with this disorder have increased levels of homocysteine in the blood and urine. Onset is typically in infancy, and clinical symptoms include seizures, microcephaly, and developmental delay. Please note that although other pathogenic variants in the gene have been reported, only the presence of a founder mutation in the Bukharian Jewish population is being tested. Patients homozygous for the Bukharian Jewish mutation are expected to exhibit a severe phenotype with early onset. Lifespan is expected to be reduced.

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