Keratin Associated Protein 5-9 (KRTAP5-9)

A variant polypeptide was present in about 5% of Caucasians. Family studies showed codominant inheritance. No correlation with color, thickness or texture could be determined. Physical properties other than the electrophoretic ones were normal. A rather wide variability in hair from different individuals is indicated by quantitative amino acid composition, particularly of cysteine and tyrosine. Certain portions of the molecule may require high specificity and therefore be restrictive in their composition, whereas others may be more permissive.Hair keratin proteins are classified into 2 large groups, the intermediate filament (IF) proteins and the intermediate filament-associated, or matrix, proteins (IFAPs); within each group the proteins can be further classified into 2 or more families. The hair IF keratin genes comprise 2 families, designated type I and type II, with 4 major components in each.