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5,10-Methylenetetrahydrofolate reductase deficiency with progressive polyneuropathy in an infant

Megumi Tsuji1, Atsushi Takagi, Kiyoko Sameshima

  • 1Division of Neurology, Kanagawa Children's Medical Center, Yokohama, Japan.

Brain & Development
|September 21, 2010
PubMed

Insights

5,10-Methylenetetrahydrofolate reductase (MTHFR) deficiency, a common folate metabolism disorder, can cause severe neurological issues in infants. Early betaine treatment may improve outcomes for infants with MTHFR deficiency and developmental delays.

Area of Science:

  • Biochemistry
  • Genetics
  • Pediatrics

Background:

  • 5,10-Methylenetetrahydrofolate reductase (MTHFR) deficiency is the most common inherited disorder of folate metabolism.
  • Clinical presentations range from asymptomatic to severe neurological impairment, predominantly affecting the central nervous system in infants.

Observation:

  • A severe infantile case of MTHFR deficiency presented with unilateral phrenic nerve palsy, hydrocephalus, and developmental delay, leading to death at 11 months.
  • Enzymatic studies confirmed MTHFR deficiency with significantly reduced activity (0.75% of control).
  • Genetic analysis identified homozygous tandem missense mutations (c.[446G>T; 447C>T]) in the MTHFR gene.

Findings:

  • The identified mutations in the MTHFR gene resulted in glycine to valine substitution at position 149 (Gly149Val).
  • Peripheral nerve involvement, such as phrenic nerve palsy, is an uncommon but possible manifestation of MTHFR deficiency.

Implications:

  • Awareness of MTHFR deficiency is crucial for infants presenting with unexplained developmental delay and rapidly progressive polyneuropathy.
  • Prompt initiation of betaine therapy after birth may mitigate symptoms by managing homocysteine and methionine levels.
  • This case highlights the importance of considering inborn errors of folate metabolism in infantile neurological disorders.

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