Genetics of human isolated hereditary hair loss disorders

Hereditary hair loss in human is a group of clinically and genetically heterogeneous disorders. It is characterized by sparse to complete absence of hair on the scalp and other parts of the body. In few cases tightly curled twisted wooly hair (WH) on the scalp has been reported as well. The hair loss disorders, including both syndromic and non-syndromic (isolated) forms, segregate either in autosomal dominant or autosomal recessive pattern. To date, seven autosomal dominant and equal numbers of autosomal recessive isolated forms of hair loss disorders have been characterized. Genes responsible for causing most of these disorders have been identified. In this review, we have provided an update on clinical and genetic aspects of isolated hereditary hair loss disorders manifesting with hypotrichosis and/or WHs. Because most of the recessive genes have been mapped using consanguineous families of Pakistani origin, therefore emphasis is given to mutations identified in these families. OMIM nomenclature has been followed to indicate different forms of hair loss disorders.