Piebaldisme: une anomalie pigmentaire à reconnaitre: à propos d'un cas et revue de la littérature

Abstract

Le Piebaldisme est une maladie autosomique dominante rare caractérisée par une anomalie congénitale de la pigmentation de la peau devenant parsemé de zones hypopigmentaires. Il est dû à une anomalie de développement des mélanocytes. Il atteint généralement la peau en exclusivité, par ailleurs il peut être associé à d'autres anomalies ou être confondu avec d'autres diagnostics différentiels. Nous présentons le cas d'un garçon de 5ans atteint de piebaldisme dans le cadre d'un phénotype dermatologique familial sans autres atteintes. Nous discuterons à travers ce cas la pathogénie, la clinique, les diagnostics différentiels ainsi que les modalités de prise en charge et les nouveaux essais thérapeutiques.

Congenital Sensorineural Hearing Loss and Inborn Pigmentary Disorders: First Report of Multilocus Syndrome in Piebaldism

“…PBT is a rare autosomal dominant genodermatosis caused by mutations in the c-kit proto-oncogene, which encodes the transmembrane receptor tyrosine kinase for mast cell growth factor (MGF, also known as stem cell factor) [9,10,11,12,13,14]. The KIT receptor and its ligand (KITLG) act as crucial factors in the control of physiological and pathological skin pigmentation through the Ras ⁄ mitogen-activated protein kinase (MAPK) signaling pathway.…”

“…Accordingly, loss-of-function KIT mutations determine defects in the survival, proliferation, differentiation, and migration of melanoblasts from the NC to the skin during early embryonic development. Consequently, patients have a significant or complete loss of melanocytes in the affected areas of the hair and skin [9,10]. PBT is clinically characterized by congenital leukoderma, leukotrichia of hair, eyebrows and eyelashes, and, rarely, heterochromia of irides, with a great variation in the degree and pattern of presentation, even within affected families.…”

“…PBT is clinically characterized by congenital leukoderma, leukotrichia of hair, eyebrows and eyelashes, and, rarely, heterochromia of irides, with a great variation in the degree and pattern of presentation, even within affected families. Specifically, piebald patients are featured by congenital, well-demarked, symmetrical, non-pigmented white patches involving the skin of the face, trunk, arms, and legs [6,9,10]. They also frequently show poliosis, traditionally known as “white forelock”, a localized patch of white hair in a group of hair follicle; it is often triangular in shape and may be the only manifestation of PBT in 80% to 90% of c-Kit carriers.…”

“…Precisely, congenital sensorineural hearing loss (SNHL) is a very common feature in WS and TS patients; conversely, it has been described more rarely in PBT and OCA subjects [4,5,6]. Table 1 synthesizes the clinical and genetic findings of all known neural crest–associated diseases characterized by hypopigmentary congenital disorders [3,4,5,6,7,8,9,10,11,12,13,14,15].…”

Progressive Depigmentation in a Patient with Panuveitis and Meningitis

“…Presence of a white forelock overlying the amelanotic skin may be the only manifestation is most individuals. Pathogenesis involves a mutation of the c-Kit gene leading to abnormal melanocyte migration during embryogenesis [10,11]. Waardenburg syndrome also presents with poliosis and vitiligo.…”