Heterozygous promotor haplotype LXA/LYB in MBL-deficiency associated with myopathy and left ventricular hypertrabeculation/noncompaction.

AIM

To report the genetic background of mannose-binding lectin (MBL)-deficiency in a patient with recurrent infections, cardiac disease, and myopathy.

METHOD

Case report.

RESULTS

In a 47-year-old male with recurrent respiratory infections, MBL-deficiency was diagnosed. He additionally had developed left bundle-branch-block, ventricular runs, and dilative cardiomyopathy. Left ventricular (LV)-hypertrabeculation and intra-myocardial calcifications were detected earlier. At age 44 years, unclassified myopathy, manifesting as easy fatigability, myalgias, and ptosis was diagnosed. After death from a sepsis with Staphylococcus aureus, autopsy revealed endocardial fibrosis and calcification, located over the compacted as well as non-compacted segments. The patient carried the heterozygous haplotype LXA/LYB in the MBL gene. MBL-deficiency was considered responsible for recurrent pulmonary infections and sepsis. The association between MBL-deficiency, LV-hypertrabeculation, endocardial fibrosis, and calcification remains speculative.

CONCLUSIONS

MBL-deficiency due to the LXA/LYB genotype may be associated with recurrent pulmonary infections and fatal sepsis. Endocardial fibrosis and calcification results rather from LV-hypertrabeculation than MBL-deficiency.