A hair shaft abnormality characterized by ball-and-socket type of deformity along the hair shaft resembling a bamboo and thereby causing brittleness and breakage of hair strands
A bamboo hair is a type of hair abnormality in which the hair strands tend to break easily. Microscopic examination of the hair shaft reveals resemblance to a bamboo due to the regularly spaced nodules or ball-and-socket type of deformity along the hair shaft. A bamboo hair has a hair shaft with invagination of the distal portion into the proximal portion with intervening lengths of normal hair. The hair shaft therefore has thin and thick portions.
A bamboo hair is one of the symptoms of the genetic disorder, Netherton syndrome. Netherton syndrome is an autosomal recessive genetic disorder that is often associated with a defective SPINK5 gene. The SPINK5 gene is a member of the gene family cluster on chromosome 5q32. It encodes for serine protease inhibitor Kazal-type 5, an inhibitor of serine proteases and is expressed in stratified epithelial tissue. One of the main functions of this protein is in skin and hair morphogenesis. In hair, the expression of the defective gene results in an abnormal keratinization of the hair shaft, particularly in the keratogenous zone (i.e. the area above the papilla pili in the hair bulb).
- trichorrhexis invaginata