X-linked hyper
IgM (XHIM) syndrome is a rare
congenital immunodeficiency disease caused by failure of B cell to isotype switch from
IgM to other classes of
immunoglobulins in response to
infections. Recently, a molecular cloning of the gene responsible for the syndrome, the
CD40L gene has been accomplished and the gene was successfully mapped to the long arm of X chromosome at the position Xq26. We, herein, report the first case of molecular proven XHIM in a Thai boy with a classic presentation and with a confirmed mutation of the
CD40L gene.
CASE REPORT: A.S. was a 1 year 7 month old boy referred from Buriram Provincial Hospital for a work up and treatment for his
recurrent infections consisted of chronic
respiratory tract infections with
otitis media (since 6 months of age), chronic
diarrhea (since 9 months of age) and
malnutrition (
marasmus) secondary to his longstanding illnesses. He was a product of a consanguineous marriage but without history of similar illness observed in his pedigree. Abnormal laboratory works up included
IgG of 300 mg/dl,
IgA 10 mg/dl,
IgM 1,635 mg/dl, positive stool examinations for Cryptosporidium, chronic
colitis on radiographic gastrointestinal follow through study, a positive
acid fast bacillus (AFB)
stain of gastric aspirate and multiple positive bacterial cultures from various body sources. His anti-HIV serology was negative. His hospital course was significant for several bouts of
infections of gastrointestinal, respiratory, and genitourinary systems. His treatment consisted of multiple courses of
antibiotics, antituberculous drugs and
IVIG administrations. His hospital course was complicated with feeding problem from an
esophageal stricture requiring several esophageal dilatations. The analysis of
CD40L gene revealed a point mutation of exon 5 (A619T) of the
CD40L gene resulting in a stop
codon confirming that indeed he had XHIM. He died with Pseudomonas
septicemia during the waiting period for a
bone marrow transplantation from a cord-blood stem cell.