The analysis of genetically determined hair defects

A classification of genetically determined hair defects based on pathophysiologic considerations is presented to facilitate research in this area. The categories in the classification are: 1) hair with periodic defects in structure; 2) complete or partial failure of hair development manifested by sparseness; 3) hairs with structural protein abnormalities and 4) defective hairs associated with metabolic defects. The methodologies for the study of hair are discussed including a new technic to directly measure Young's modulus of elasticity. A new autosomally dominantly inherited disorder with sparse hair and milia is presented.

The genetics of human hair growth

The regulation of human hair growth is one of the most mysterious of biologic events. Genetic factors are responsible for the density, length, color and texture of hair. Heredity disorders can affect either hair alone, hair and other ectodermal structures, or can be pansystemic. This paper considers all heredity disorders which affect human hair growth. These disorders are divided into three categories: 1) the dysmorphic syndromes; 2) the modifier gene abnormalities and 3) the single major gene abnormalities. The disorders in these categories are listed, along with the mode of inheritance, cause, hair phenotype and the extent of involvement. The utilitarian function of the study of human hair growth is illustrated. Insight into problems of differentiation can be most rapidly expanded using this approach.

Congenital hair defects

Congenital hair defects are not just medical curiosities. Congenital hair defects and associated disease entities may represent different manifestations of a basic underlying metabolic defect. Abnormal hair should serve as a clue to other associated abnormalities particularly abnormal amino acid metabolism, neurosensory hearing loss, dental enamel hypoplasia and mental and physical retardation. With application of modern technics to the study of hair, new data have been obtained on the physical and biochemical properties of human hair.

The characterization of hereditary abnormalities of keratin: Clouston's ectodermal dysplasia

Ectodermal dysplasia of the Clouston type is a disease caused by a single dose of an autosomal dominant gene. It appears to involve only the skin and its appendages. An investigation of the physical and chemical abnormalities of the hair protein in this disease is beginning to throw some light on the action of the gene involved.

A classification of special problems in sex differentiation

The purpose of this discussion is to present a revised classification of both male and female hermaphroditism and to illustrate by case presentation some of the more unusual or newly recognized forms of these disorders, including forms where recent studies have helped elucidate etiology or pathogenesis.

Mental retardation, abnormal hair and mild aminoaciduria, all of unknown aetiology, in siblings

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Sibs with mental and physical retardation and trichorrhexis nodosa with abnormal amino acid composition of the hair

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Bloch-Sulzberger Syndrome (incontinentia pigmenti)

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