The mutation is a dinucleotide transition in adjacent nucleotides (GC to AT) at positions 1972 and 1973 (Genbank Accession NM_010864), in exon 13 of 41 exons, that changes two codons such that two amino acids in the head region of the protein are altered: methionine at amino acid position 515 is replaced by isoleucine (p.M515I) and proline at position 516 by serine (p.P516S). (J:133117)