Clinical and molecular diagnostic criteria of congenital atrichia with papular lesions

Genetic Hair Disorders: A Review

Hair loss in early childhood represents a broad differential diagnosis which can be a diagnostic and therapeutic challenge for a physician. It is important to consider the diagnosis of a genetic hair disorder. Genetic hair disorders are a large group of inherited disorders, many of which are rare. Genetic hair abnormalities in children can be an isolated phenomenon or part of genetic syndromes. Hair changes may be a significant finding or even the initial presentation of a syndrome giving a clue to the diagnosis, such as Netherton syndrome and trichothiodystrophy. Detailed history including family history and physical examination of hair and other ectodermal structures such as nails, sweat glands, and sebaceous glands with the use of dermoscopic devices and biopsy all provide important clues to establish the correct diagnosis. Understanding the pathophysiology of genetic hair defects will allow for better comprehension of their treatment and prognosis. For example, in patients with an isolated hair defect, the main problem is aesthetic. In contrast, when the hair defect is associated with a syndrome, the prognosis will depend mainly on the associated condition. Treatment of many genetic hair disorders is focused on treating the primary cause and minimizing trauma to the hair.

Atrichia congenita

Atrichia congenita is a rare genodermatoses is characterized by a mutation of the human hairless (HR) gene on chromosome 8p22. There is loss of scalp hair between one to six months of age, after which no growth occurs. Eyebrow, eyelash, and body hair may also be sparse or absent; patients may have a few pubic and axillary hairs. The condition may present in isolation or along with other defects.

Mutations in the hairless gene underlie APL in three families of Pakistani origin

BACKGROUND

Atrichia with papular lesions (APL) (OMIM#209500) is a rare autosomal recessively inherited form of irreversible alopecia characterized by papular lesions of keratin-filled cysts on various regions of the body. Males and females are equally affected and present with a distinct pattern of total hair loss on scalp, axilla and body. It begins shortly after birth with the development of hair loss, and patients are normally devoid of eyelashes and eyebrows. Mutations in the hairless (HR) gene have been previously shown to be responsible for APL.

OBJECTIVE

In this study, we studied the molecular basis of APL in three unrelated families of Pakistani origin.

METHOD

Molecular analysis of the HR genes was performed on genomic DNA from probands and family members.

RESULTS

DNA sequencing of the HR gene in family A revealed a novel homozygous 2bp deletion in exon 6 leading to a frameshift and a downstream premature termination codon in exon 8 (1782-83delAG). In family B, we identified a novel homozygous deletion of a G nucleotide at the exon 15-intron 15 boundary, termed 3097delG. Family C carries a previously reported missense mutation consisting of an A-to-G transition at nucleotide 276 resulting in the mutation N970S in exon 14.

CONCLUSION

Two mutations identified in this study are novel mutations in the HR gene and extend the body of evidence implicating the hairless gene family in the pathogenesis of human skin disorders. The one previously reported mutation suggests it may represent a recurrent mutation, or alternatively, an allele that is widely dispersed around the world.

Female pattern hair loss and its relationship to permanent/cicatricial alopecia: a new perspective

Female pattern hair loss (FPHL) is a common hair disorder of the central scalp. The clinical change in hair density, related to a change in the hair cycle and miniaturization of the hair follicle, is generally considered to be potentially reversible. However, there is now evidence of a permanent hair loss that develops in a subset of women with FPHL. The presence of a perifollicular lymphohistiocytic infiltrate and fibrosis is seen without follicular drop-out in biopsies of women with FPHL and with a notable follicular drop-out in a cicatricial form of this condition (heretofore called cicatricial pattern hair loss) as well as in fibrosing alopecia in a pattern distribution, currently classified as a subset of lichen planopilaris. The potential relationship of these conditions as well as frontal fibrosing alopecia and central centrifugal cicatricial alopecia, two other conditions of permanent hair loss seen primary in women, is discussed.