Identification of L394R mutation. (A) Schematic representation of human γ-glutamyl carboxylase gene structure showing the situation of exons. In detail is a fragment of exon 9 sequence containing the nucleotide substitution at codon 394. The transversion T to G (underlined) at that position causes a Leucine to Arginine replacement in the protein. (B) Direct sequencing of the genomic DNA from one patient depicts homozygosity for the mutation. (C) Analysis of L394R mutation by PCR. Electrophoresis of amplified DNA using the mutated oligonucleotide designed to introduce an Alu I restriction site in normal allele but not in mutant allele. Lane 1, normal control; lane 2, patient’s DNA homozygous for the mutant allele; lane 3, heterozygous pattern.