Table 1 Summary of the numbers of case triads/dyads successfully genotyped for MTHFR 677C→T and 1298A→C polymorphisms.

		MTHFR 677C→T		MTHFR 1298A→C		Both polymorphisms
Complete trios		284		268		249
Mother–child dyads		57		67		55
Father–child dyads		6		8		11
Total		347		343		315

MTHFR, methylenetetrahydrofolate reductase.