Genetic and phenotypic heterogeneity of multiple lentigines and precise diagnosis in four Chinese families with multiple lentigines.

Lentigines are well-defined, small, brown macules resulting from the accumulation of melanin content in the basement membrane zone with an increase in the number of melanocytes. Hereditary multiple lentigines (ML) can be associated with multiple genes and are not commonly encountered in clinical practice. Patients can solely have skin involvement or present with multisystemic deformative phenotypes. This study aimed to describe four unrelated Chinese families presenting with ML as their first visit symptom. We performed whole-exome sequencing (WES) and Sanger sequencing on all patients and immediate family members for precise molecular diagnosis. Two novel variants c.1548 T > A (p.Ser516Arg) and c.1811C > A (p.Thr604Lys) in SASH1, and two recurrent variants c.1403C > T (p.Thr468Met) and c.1493G > T (p.Arg498Leu) in PTPN11, were identified in these four families. We also summarized the genes associated with ML and differential diagnosis of pigment abnormality. We suggested that the molecular diagnosis of ML should be emphasized because it can help in the clinical differential diagnosis and further genetic counseling and prognosis.