Long term follow-up of children with mixed connective tissue disease.

Mixed connective tissue disease (MCTD) is characterized by features of more than one of the rheumatic disorders with antinuclear antibodies in a speckled pattern and with antibodies to nuclear ribonucleoprotein (nRNP). MCTD is uncommon in children and long-term follow-up studies in children are infrequently reported. A retrospective review of clinical experience at five pediatric rheumatology centers provided 11 patients who met the following inclusion criteria: (1) Kasukawa's criteria for MCTD1; (2) presentation younger than 18th birthday; (3) greater than five years of follow-up; (4) completion of data collection form. The widely varying outcomes of these 11 children with MCTD on long-term follow-up may lend doubt that this is a unique and distinctive rheumatologic disorder.