Abnormality of the Hair in Cartilage-Hair Hypoplasia

Abstract

The scalp hair in a patient with cartilage-hair hypoplasia was studied by light-microscopy, amino-acid analysis and tensile testing. Measurement of the hair shaft diameter, using an ocular micrometer, confirmed McKusick’s observation that the hairs were thinner than those seen in normal individuals. They were also weaker than normal hair, even when the smaller cross-sectional area was taken into account. However, no differences could be detected on amino-acid analysis between the patient’s and control hair. It was suggested that the findings were consistent with shorter keratin chain length in the patient’s hair.

Biophysical and biochemical studies of the hair in cartilage‐hair hypoplasia

“…The reversibility with mild oxidation, normal testing in air, normal sulfur analysis, and the normal protein electrophoresis of the DTT extracted hair and similarity of amino acid analysis of normal and CHH hair further suggested that the defect is not due to a major structural deficiency of the hair proteins. None of our data supported the suggestion (Coupe & Lowry 1970) that decreased filament length is responsible for the mechanical properties of CHH hair.…”

“…The hair in CHH hair was thinner (Mc Kusick et al 1965) and lighter in color than normal (McKusick et al 1965), and was occasionally ellipsoidal (Coupe & Lowry 1970). It had a normal microscopic structure under scanning electron microscopy except for increased spacing between overlapping cuticular scales (Brown 1971).…”

Cartilage hair hypoplasia.

“…The other striking feature which distinguishes this from the other types of metaphyseal dysostosis is the very short, fine, sparse scalp hair. Coupe and Lowry (1970) have analysed hair from typical cases and found a normal amino acid content, but a thin structure with lower tensile strength and the lack of a central pigment core, which is present in normal hair. The hair from our patient shows the first two features.…”

Overlap syndrome: a diagnostic dilemma

“…The basic defect is not known but there may be decreased reactivity of some disulphide bonds in hair leading to its abnormal biophysical and biochemical properties 10 11. It is an autosomal recessive disorder with reduced penetrance.…”