Trial Information

Determining the Pathogenesis of Systemic Pediatric-Onset Mastocytosis

Mastocytosis in infants and children is an unusual disease characterized by an excess of
mast cells in tissues. In pediatric onset mastocytosis, disease is usually localized to the
skin and disease is considered to be of limited duration. However, a subset of children
appear to develop a clinical picture resembling that observed in adults who have adult-onset
disease. This study will focus on children with more severe mastocytosis in an attempt to
define its pathogenesis, focusing on mutations and polymorphisms in genes regulating mast
cell proliferation and survival to determine if they might contribute to this disease
pattern. If severe pediatric-onset disease does not fit within the existing classification,
new criteria of diagnosis must be proposed for the pediatric age group.

This study will examine children and young adults age birth to 21 years with pediatric-onset
disease previously enrolled on NIAID mastocytosis protocols, or as a result of physician
referral, which have disease more consistent with adult-onset disease or parameters
associated with increased morbidity. The evaluation may include serum tryptase, blood
count, bone marrow biopsy and aspirate, morphology and mutational analysis. Subjects may be
asked to return in 12-24 months for assessment. If relevant mutation effecting mast cell
growth and function are identified, such mutations will be sought in the biologic parents as
appropriate, but only when such mutations are believed to be germ line (not somatic)
mutations. This study will aid in the understanding of the characteristics of severe
mastocytosis in the pediatric age group.