Incidence of Clinically Diagnosed Digeorge Syndrome in Olmsted County, Minnesota

Rationale:

DiGeorge syndrome (DGS) is most commonly caused by a 22q11.2 chromosomal deletion, although more rare genotypes have been identified.   With an estimated incidence of 1 in 4000 births the syndrome’s phenotype is highly variable. The aim of this study is to characterize the incidence of DGS.

Methods:

A retrospective study was conducted using the unique record linkage system in Olmsted County database using Rochester Epidemiology Project (REP).

Results:

There were a total of 17 subjects (6 males and 11 females) with clinically diagnosed DGS over the 10 year period. The overall incidence of DGS was 1.1/100000 person –years. The event rate was 5.2/10,000 births in Olmsted county over the 10 year period, which translates to 1/2000 children born in Olmsted county. The median age of diagnosis was 0.9 years with a median duration of follow up of 7 years.

The prevalence of autoimmune cytopenia and thyroid dysfunction was 30%. 82% of the subjects had developmental delays.

None of the subjects had IgE mediated reactions to food, 40% had allergic rhinitis and 38% had clinically diagnosed asthma/reactive airway disease. Recurrent infections were common in this cohort (76%), with frequent tympanostomy tubes placement (65%) and hearing loss (68%).

Conclusions:

This is one of the first population-based studies examining the incidence of DGS in Olmsted County. There is a higher than previously reported incidence of about 1/2000 births.

The patient’s age at diagnosis depends on the severity of their phenotype with cardiac defects being the most common reason for genetic identification earlier in life.