Identification of two novel mutations in the PLCD1 gene in Chinese patients with hereditary leukonychia

Hereditary leukonychia (HL) is a rare nail dystrophy disease, and several different clinical manifestations and mutations in the phospholipase C delta 1 (PLCD1) gene have been reported. The present study reports on one Chinese family and one sporadic case of with HL. The family members exhibited an autosomal dominant pattern of inheritance with the involvement of all the fingers and toenails in all the patients. Of interest, most of the affected members had koilonychia during their childhood. Thus, the present study first used gene mapping with an aim to identify the pathogenic gene underlying koilonychia. Through genome-wide linkage analysis, the pathogenic area of koilonychia was identified on chromosome 3 with multipoint Log of Odds scores >2. A novel pathogenic mutation c.1384G>A (p.E462K) was identified in the PLCD1 gene in all the patients in the family, which confirmed the diagnosis of hereditary leukonychia. A novel mutation c.770G>A (p.R257H) was also detected in one sporadic case of leukonychia. On the basis of these findings and of previous studies, it is suggested that hereditary leukonychia may initially present as koilonychia, whereas hereditary koilonychia does not progress to leukonychia. Moreover, the present study identified two pathogenic variants of the PLCD1 associated with hereditary leukonychia, and highlights the significance of genetic diagnosis.