Patterned cutaneous hypopigmentation phenotype characterization: A retrospective study in 106 children

Abstract

Background Cutaneous patterned hypopigmentation's phenotype is highly variable and may be associated with extracutaneous anomalies. Objective We evaluated the phenotypic and clinical characteristics of patients with cutaneous patterned hypopigmentation to determine whether certain patterns were more likely to be associated with underlying anomalies. Methods The charts of 106 children with cutaneous patterned hypopigmentation were reviewed retrospectively (2007‐2018) at Sainte‐Justine University Hospital Centre, in Montreal, Canada. Retrieved information included sex, age at diagnosis, phototype, pattern, and distribution of the cutaneous lesions and the presence of extracutaneous findings. Data were recorded on a software tool which collects and analyzes phenotypic information. Results The predominant types of cutaneous patterned hypopigmentation were along Blaschko's lines in narrow (38.7%) and broad bands (53.8%). Mixed patterns were observed in 22.5% of children. The anterior trunk and posterior trunk were most frequently affected (69% and 56%, respectively). Extracutaneous involvement, especially neurological and developmental, was present in 28.3% of patients and was significantly associated with ≥ 4 involved body sites. Conclusion Distribution and types of cutaneous patterned hypopigmentation were not predictive of extracutaneous findings, with the exception of multiple sites involvement and possibly centrofacial location and blocklike lesions. Follow‐up until school entry should help identify subtler associated extracutaneous anomalies.

Low rates of neurological abnormalities in patients with pigmentary mosaicism: A retrospective cohort study from a tertiary dermatology center

“…These low rates of NA in our population mirror low reported rates in the recent dermatology literature 4,6,14 compared to the high rates initially reported predominantly in neurology literature, likely indicating there may have been a component of referral bias 2,3,6,8,13 . It is also notable that prior reports often had narrow inclusion criteria, examining patients with only certain pigment color and patterns 4,15 . A 2018 literature review of 174 articles that included 651 patients with PM of various colors and patterns identified developmental delay in 198 (30.41%) and seizures in 137 (21.04%), and demonstrated higher rates of extracutaneous (musculoskeletal and neurologic) features in patients with mixed hyper and hypopigmented lesions, which we did not find in our population 8 .…”

“…Pigmentary mosaicism (PM) is a descriptive term that encompasses a broad range of patterned hyper‐ and hypo‐pigmented phenotypes, thought to reflect underlying genetic mosaicism of skin cells 1–7 . Mosaicism refers to the creation of two or more distinct cell populations derived from a single zygote 8 .…”

“…Even in the earliest reports, there was acknowledgement of the incongruent rates of neurologic manifestations when comparing neurology and pediatric literature versus those reported in dermatology literature 3,6,8 . More recent reports of PM patients presenting to dermatologists indicate that rates of NA are significantly lower (15%–30%), and that certain patterns (e.g., blocklike) and pigmentation (e.g., hypopigmented) may have higher risks of extracutaneous manifestations than others 4–8,14 …”

“…Studies investigating PM have varied extensively in design, including patients with only certain patterns (e.g., blaschkolinear lesions) or pigmentary changes (only hyperor hypopigmented lesions). 4,13,15 Terminology has also varied over time. Initial reports of extensive hypopigmentation were described as hypomelanosis of Ito and incontinentia pigmenti achromians.…”

A novel pathogenic RHOA variant in a patient with patterned cutaneous hypopigmentation associated with extracutaneous findings

“…In our retrospective study of 106 children with patterned cutaneous hypopigmentation (PCH), the predominant types of patterns were along Blaschko lines type 1a and type 1b, whether or not extracutaneous anomalies were present 10 . Although not statistically significant, type 1a pattern of hypopigmentation was more frequently associated with extracutaneous findings than type 1b, 34.1% vs. 21%, respectively.…”