Comparison of the Familial and Sporadic Forms of Hyper IgM Syndrome in the Iranian Patients

Hyper IgM (HIGM) syndrome or immunoglobulin class-switch recombination deficiency (Ig-CSR) is a group of primary immunodeficiencies (PIDs) where B cells are unable to undergo the process of immunoglobulin class -switching recombination (CSR), a process in which B-cells modify their DNA to switch from production of IgM to other immunoglobulins. Hence, the affected patients exhibit normal to high levels of serum IgM and low or absence of other immunoglobulin isotypes relative to mean values of age. Therefore, the present study was conducted to assess the demographic data, clinical manifestation, and immunological findings in the sporadic and familial types of HIGM.

Demographic data, laboratory findings, and clinical presentations of 79 Iranian patients diagnosed with HIgM syndrome were collected. All the patients were classified into two different groups: sporadic and familial types of HIGM.

Male to female ratio was significantly higher in the familial group compared to the sporadic group so that, 94.7% of the patients were male in the familial group, while only 70% of the sporadic patients were male (P=0.032). It was also found that the familial group had a significantly higher consanguinity rate (P=0.047) and a significantly lower delay of diagnosis compared to the sporadic group (P=0.006). The lower respiratory infection (42%) followed by upper respiratory infection (26%) and diarrhea (15%) were the most frequent initial presentations. It was shown that diarrhea, as an initial presentation was about three times more common among the familial group (31.6%) compared to the sporadic group (10%, P=0.028). Otitis was also found to be more prevalent in the sporadic group (P=0.042).

Our findings could be explained by more careful screenings and more vigilant and informative parents in the families with another affected member.