Acne conglobata in a long-term survivor with trisomy 13, accompanied by selective IgM deficiency.

Trisomy 13 (T13) is a congenital chromosomal disorder that is usually fatal within 2 years of birth, and only a few patients have been reported to reach adolescence. Here, we report a male long-term survivor of T13, currently 15 years of age, with a several-year history of extensive acne conglobata (AC) with abscesses on the face and neck. Methicillin-resistant Staphylococcus aureus was consistently isolated from the pustular lesions. Serum IgM levels were extremely low at 10 mg/dl. There were no abnormalities in neutrophil and total B cell number, or in serum IgA and IgG levels. Increased CD8+ T cell counts and inversion of the CD4/CD8 ratio were observed repeatedly. The patient's clinical features and laboratory data support a diagnosis of selective IgM deficiency (SIgMD) with concurrent AC. Immunoglobulin replacement therapy elevated serum IgM levels to the normal range and reduced the severity of AC. We suggest that T13 may represent a syndromic disorder associated with multiple organ malformation and a risk of developing immunodeficiency involving SIgMD. Because pediatric SIgMD is rare and an immunological abnormality in T13 patients has not previously been reported, we describe the patient's clinical course.