Background and Aims

C5 Deficiency is a rare autosomal recessive primary immunodeficiency disease, associated with recurrent or severe infections by Neisserial species.

We report a new mutation in a previously healthy 44-year-old woman, who developed a meningococcal sepsis by the Y strains of Neisseria who later developed sensorineural hearing loss and sensory-motor polyneuropathy responsive to steroids.

Methods

Complement study

C5 gene study

Results

C3 107 mg / dL [80-130], C4 17 mg / dL [10-22], CH50 1.1 IU / ml [35-90], MBL Activity 3.6% [10-125], Classical Activity 1.8% [ 60 - 140], Alternative Activity 2% [10 - 120]

C5 3.4 mg / dL [10.26-26.3], C6 16.8 mg / dL [7.1 - 12.8], C7 10.3 mg / dL [4-11]. C8 28.6 mg / dL[10.7-24.9].

Immunocomplexes: Negative

C5 gene study: deletion in exon 35, c.4330del, in both alleles with premature stop codon at position 1464 of the p(Glu1444Lysfs * 21). Parents were born at different locations, were not consanguineous and were heterozygous for the deletion herein described.

Conclusions

Severe meningococcal disease by Y strains is uncommon in Europe and the mutation of our patient has not been previously reported. Since parents were not consanguineous, it suggests that the carrier state for this deletion might be more frequent than expected in the spanish population. Interestingly, the clinical picture after infection, presumptively suggest an inmunomediated sensorineural hearing loss and sensory-motor polyneuropathy, although it seems not due to immunocomplexes.