KRT81

The protein encoded by this gene is a member of the keratin gene family. As a type II hair keratin, it is a basic protein which heterodimerizes with type I keratins to form hair and nails. The type II hair keratins are clustered in a region of chromosome 12q13 and are grouped into two distinct subfamilies based on structure similarity. One subfamily, consisting of KRTHB1, KRTHB3, and KRTHB6, is highly related. The other less-related subfamily includes KRTHB2, KRTHB4, and KRTHB5. All hair keratins are expressed in the hair follicle; this hair keratin, as well as KRTHB3 and KRTHB6, is found primarily in the hair cortex. Mutations in this gene and KRTHB6 have been observed in patients with a rare dominant hair disease, monilethrix.

Keratin 81

Cytosol
Extracellular space
Keratin filament

Monilethrix (MNLIX):
A disorder clinically characterized by alopecia and follicular papules. Affected hairs have uniform elliptical nodes of normal thickness and intermittent constrictions, internodes at which the hair easily breaks. Usually only the scalp is involved, but in severe forms, the secondary sexual hair, eyebrows, eyelashes, and nails may also be affected.