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Observational Study
. 2021 Feb;84(2):415-424.
doi: 10.1016/j.jaad.2020.01.078. Epub 2020 Feb 7.

Hypertrichotic patches as a mosaic manifestation of Proteus syndrome

Deeti J Pithadia  1 , John W Roman  1 , Julie C Sapp  2 , Leslie G Biesecker  2 , Thomas N Darling  3
Affiliations
Observational Study

Hypertrichotic patches as a mosaic manifestation of Proteus syndrome

Deeti J Pithadia et al. J Am Acad Dermatol. 2021 Feb.

Abstract

Background: Proteus syndrome is an overgrowth disorder caused by a mosaic activating AKT1 variant. Hair abnormalities in Proteus syndrome have rarely been reported, and frequencies of such findings have not been elucidated.

Objective: To define the types and frequencies of hair findings in individuals with Proteus syndrome.

Methods: A cross-sectional study was conducted of individuals with clinical features of Proteus syndrome and a confirmed pathogenic variant in AKT1 evaluated between November 1996 and June 2019 at the National Institutes of Health Clinical Center. Medical records were reviewed for patterning, density, and color of hair on the body and scalp.

Results: Of 45 individuals evaluated, 29 (64%) had asymmetric hypertrichosis on the body. This included unilateral blaschkoid hypertrichotic patches overlying normal skin or epidermal nevi in 16 (36%), unilateral nonblaschkoid hypertrichotic patches in 11 (24%), and unilateral limb hypertrichosis in 10 (22%). Diffuse, scattered, or patchy changes in scalp hair density or color were present in 11 individuals (24%).

Limitations: The retrospective, observational design, and limited longitudinal follow-up.

Conclusions: Asymmetric variations in hair distribution, thickness, length, and color contribute to the overall mosaic appearance of the skin in Proteus syndrome, an observation that provides novel insights into the role of phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) signaling in skin appendage development.

Keywords: AKT; AKT1; Blaschko lines; Proteus syndrome; hair; hair follicles; hypertrichosis; mosaicism.

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Conflict of interest statement

The authors have no conflicts of interest to declare.

Figures

Figure 1:
Figure 1:
Linear, blaschkoid hypertrichosis on the left shoulder. Some regions of hypertrichosis show no apparent changes to the underlying skin, while others have faint hyperpigmentation.
Figure 2:
Figure 2:
Hypertrichosis on the back following the distribution of Blaschko’s lines. The hypertrichosis overlies an epidermal nevus ranging in appearance from hyperpigmented patches to slightly-elevated plaques.
Figure 3:
Figure 3:
Overgrowth of the left leg with associated hypertrichosis.
See this image and copyright information in PMC

References

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