An X-linked gene involved in androgenetic alopecia: a lesson to be learned from adrenoleukodystrophy

Abstract

Background: Adrenoleukodystrophy (ALD), including its adult variant adrenomyeloneuropathy (AMN), is an X-linked recessive trait characterized by progressive demyelinization of the nervous system. The gene defect involves a peroxisomal transporter protein, resulting in accumulation of very-long-chain fatty acids in the brain and other organs such as the adrenal glands. Affected men show various endocrine disorders. Moreover, disturbances of hair growth are frequently mentioned in reports on ALD/AMN.

Objective: This study was performed to delineate further the hair status and type of hair loss in men with AMN.

Methods: We examined and documented the status of hair growth in 16 men suffering from AMN. A meticulous history with particular regard to hair changes was taken from all patients and their family members.

Results: The age of the patients varied between 27 and 62 years, their mean age was 39.8 years. Twelve men showed male-pattern androgenetic alopecia (AGA), Hamilton grades IV-VIII, 3 men had a female-pattern AGA (Ludwig grade I or II). Ten of the patients with male-pattern AGA had reached Hamilton stage VII or VIII. The remaining scalp hair was unusually scarce and thin in 11 cases, regardless of the grade of AGA. Moreover, in 10 of 16 patients the eyelids showed pronounced madarosis. The remaining body hair was found to be normal. If present, endocrine manifestations had started prior to the onset of alopecia, and in 11 of 12 patients hair loss was apparent before neurological symptoms were noted.

Conclusion: ALD/AMN gives rise to two different types of hair loss. Firstly, affected men show diffuse hair loss involving the entire scalp and the eyelashes. Secondly, they tend to develop AGA more frequently and earlier and in a severer form. Paradoxically, pronounced AGA is present although the patients may simultaneously show some degree of hypogonadism. Hence, the X-linked ALD mutation can be taken as a well-defined gene within the polygenic spectrum of genes responsible for AGA. This may be of theoretical importance for the elucidation of the pathogenetic pathways of AGA.