Skin mastocytosis with short stature, conductive hearing loss and microtia: a new syndrome

A Review of the Clinical Features and Management of Systemic Congenital Mastocytosis through the Presentation of An Unusual Prenatal-Onset Case

Mastocytosis is a heterogeneous group of rare hematological disorders that can occur in infancy. We report a 16-year-old girl who presented with an aggressive form of systemic congenital mastocytosis, associated with a significant global developmental delay, deafness, and multiple anomalies. At 4 years of age, she developed a germinoma presenting as an invasive spinal mass. Extensive cytogenetic, metabolic, and molecular genetic studies that included whole-exome sequencing studies revealed a KIT alteration (NM_000222.3(KIT):c2447A > 7 pAsp816Val) and likely pathogenic variant in the DNA from peripheral blood and skin lesions. C-kit was also found to be overexpressed in the spinal tumor cells. We compared the features of this child to those of six previously reported pediatric patients with cutaneous mastocytosis, microcephaly, microtia, and/or hearing loss reported in OMIM as mastocytosis, conductive hearing loss, and microtia (MIM 248910), for which the etiology has not yet been determined. This report extends the currently recognized spectrum of KIT-related disorders and provides clues as to the potential etiology of a syndromic form of congenital mastocytosis. International efforts to understand the benefits of long-term targeted therapy with tyrosine kinase inhibitors for this KIT-altered rare disease should continue to be evaluated in clinical trials.

Apparent third patient with cutaneous mastocytosis, microcephaly, conductive hearing loss, and microtia

Mastocytosis refers to a heterogeneous group of rare disorders characterized by an abnormal accumulation of mast cells in one or more organ systems. Cutaneous mastocytosis (CM) is the most frequent form in children and is characterized by hyperpigmented macules or papules symmetrically distributed over the trunk, and less so over the limbs, neck, and scalp. Two published articles have reported on unrelated girls presenting with mastocytosis, microcephaly, hearing loss, and hypotonia. Based on the original observation, this disorder was defined as CM with short stature, conductive hearing loss, and microtia (OMIM 248910). Here we report on a girl with similar manifestations who corroborates the existence of this rare disorder. CM, microcephaly, microtia, and/or hearing loss are the minimal diagnostic criteria. All the known patients were sporadic, but parental consanguinity in the first case argues for a possible autosomal-recessive inheritance.

Familial mastocytosis associated with neurosensory deafness

Mastocytosis is a disease characterized by excessive accumulation of mast cells in different tissues and symptoms caused by the release of mast cell mediators. The skin is frequently directly involved in mastocytosis. The disease is rarely seen in other members of the subjects' family; only 49 cases of familial mastocytosis have been reported. Familial mastocytosis associated with hearing loss may represent a newly described inherited entity. We describe a brother and sister exhibiting skin mastocytosis and neurosensory deafness, associated with a history of hearing loss in their father's family. The appearance of the mast cell disease in two siblings, who presented with similar clinical features represents a familial form of mastocytosis; the association with an inherited form of deafness may constitute a new syndrome. Our patients show several features similar to some previously reported cases but different insofar that additional congenital defects and mental retardation are absent.