Hormonal profile and androgen receptor study in prepubertal girls with hypertrichosis

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Publisher: BioMed Central Ltd.
Document Type: Article
Length: 3,772 words
Lexile Measure: 1470L

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Author(s): Maria Isabel Hernandez1 , Andrea Castro1 , Ketty Bacallao1 , Alejandra Avila1,2 , Aníbal Espinoza3 , Leon Trejo1 , Germán Iéiguez1 , Ethel Codner1 and Fernando Cassorla1

Introduction

Prepubertal hypertrichosis is a reportedly benign condition characterized by an excessive growth of vellous hair in non-androgen dependent areas of the body compared to the amount usually present in normal subjects of the same age, race and sex [1]. Characteristically, the hair in subjects with hypertrichosis usually grows on the trunk, arms and legs. This form of hypertrichosis was described by Barth et al. in 1988 [2], and differs from universal congenital hypertrichosis [3, 4] and hypertrichosis laguginosa [5]. Although this condition is usually considered idiopathic and regarded as benign, it may be very disturbing cosmetically, causing significant patient and parental anxiety. In addition, hypertrichosis may be associated with metabolic or genetic disorders, and with the use of drugs [6-11].

Studies concerning the hormonal profile of subjects with hypertrichosis are relatively few and difficult to compare, due to the various definitions of this condition. In addition, the investigation of androgen metabolism has not shown significant differences between girls with hypertrichosis and controls [12, 13].

The human androgen receptor (AR) is the main regulator of androgen signaling in the cell [14] and is encoded by the AR gene encoded in the X-chromosome [15]. The transactivator domain of the AR protein contains two polymorphic trinucleotide repeats segments that encode poly -glutamine (CAG)n and -glycine (GGN)n tracts within exon 1. There are considerable data linking the length of CAG repeats to androgen sensitivity in vivo as well as in vitro, that suggests an inverse relationship between length repeats and androgen receptor sensitivity [16]. In the case of GGC, AR with repeats number other than 17 GGC(23GGN), exhibit lower transactivation in response to androgens, suggesting a relationship between repeat lengths and AR function [16].

The aim of our study was to evaluate the clinical and hormonal characteristics of a large group of girls with hypertrichosis, and to assess the number of CAG and GGC repeats in their androgen receptor gene.

Subjects and methods

Subjects

A group of 42 prepubertal girls with hypertrichosis was recruited from our endocrine clinic, and matched by age with a group of 29 prepubertal control girls without hypertrichosis. The age of both groups of girls ranged between 2 to 8 years. Exclusion criteria were: 1) Any clinical sign of puberty according to Marshall and Tanner stages, ultrasonography or hormonal profile. 2) Chronic disease (including congenital adrenal hyperplasia) 3) Medication that could induce hypertrichosis or hyperandrogenism. 4) Low birth weight and 5) Maternal history of polycystic ovary syndrome.

Study protocol

After an overnight fast, all girls were evaluated at the Institute of Maternal and Child Research of the University of Chile. The patients and control girls underwent a careful physical examination performed by a single pediatric endocrinologist (MIH), to determine their hypertrichosis score according to Gryngarten et al. [13]. As indicated by this author, a score above...

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Gale Document Number: GALE|A541250850