Abstract
KIT mutations were, at one point, believed to be the only mutations associated with cutaneous mastocytosis (CT), a rare dermatological condition characterized by the dysregulated multiplication of mast cells within the skin. However, in recent years, a new variant of cutaneous mastocytosis associated with GNB1 mutations and developmental delay was discovered. As of May 2023, only five cases of GNB1-mutation associated cutaneous mastocytosis have been reported. The purpose of this study is to analyze commonalities in mutation variants, demographics, and dermatopathological and clinical findings in cases of GNB1-associated CT. The PubMed database was searched in May 2023 using the query (gnb1) AND ((cutaneous mastocytosis) OR (urticaria pigmentosa) OR (urticaria pigmentosum)). Criteria for inclusion was to be focused on both GNB1 mutations and CT, and to be discussing unique cases. A total of 4 articles comprising 5 cases of GNB1-mutation associated CT were identified. All were Caucasian children under 6 years. The first case involved a p.Gly77Val mutation. Three additional cases involved p.Ile80Thr mutations. A fifth and final case involved a p.Ile80Asn mutation. Pathological analyses showed the abnormal accumulation of mast cells, consistent with findings expected in CT. Common clinical findings included numerous hyperpigmented maculopapular lesions, positive Darier sign, developmental delay, hypotonia, and neurological sequelae.