Clinical and Genetic Characterization of 8 Patients with Syndromic Patterned Cutaneous Hypopigmentation: A Descriptive Study.

Background: Patterned cutaneous hypopigmentation (PCH) can be associated with an array of extracutaneous findings.

Objective: Determine clinical and genetic characteristics of patients with PCH with extracutaneous involvement.

Method: Thirty patients were identified, and eight patients with neurological involvement agreed to participate in this study. They were reassessed to collect clinical anomalies associated with their PCH. Exome sequencing was performed on patient blood and lesional skin biopsies as well as blood from both parents when available. Array comparative genomic hybridization was performed on patients' skin and blood samples.

Results: Narrow and broad bands along the lines of Blaschko were observed in 8 and 5 patients, respectively. Musculoskeletal, acral; ophthalmologic; and dental anomalies were observed in 7 patients. A chromosomal or monogenic cause of syndromic PCH was identified in all patients: 3 mosaic chromosomal abnormalities found (trisomy 7, trisomy 14, and 13q13-ter deletion) and pathological de novo germline and somatic mutations in 3 (NBEA, USP9X, and DDX3X) and 2 patients (NIPBL and RHOA).

Limitations: Single-centre and retrospective study.

Conclusion: Through better clinical characterization of syndromic PCH, we will improve our understanding of these disorders. We believe that all patients with PCH with systemic findings should undergo comprehensive genomic evaluations of lesional skin and peripheral blood.