Abstract: SA-PO630

Fabry’s Disease within Dialysis Patients in Madeira Island: An Unexpected Surprise

Session Information

Category: Genetic Diseases of the Kidney

  • 803 Genetic Epidemiology and Other Genetic Studies of Common Kidney Diseases

Authors

  • Pestana, Maria Nicole, Hospital Central do Funchal, Funchal, Portugal
  • Durães, José Mário, Hospital Central do Funchal, Funchal, Portugal
  • Gomes da silva, Ana Francisca, Hospital Central do Funchal, Funchal, Portugal
  • Goncalves, Miguel, Hospital Central do Funchal, Funchal, Portugal
  • Vieira, Pedro M S, Hospital Central do Funchal, Funchal, Portugal
  • Resende, Luís, Hospital Central do Funchal, Funchal, Portugal
  • Guimaraes Rosa, Jose Nuno, Hospital Central do Funchal, Funchal, Portugal
  • Teixeira, José, Hospital Central do Funchal, Funchal, Portugal
  • Silva, Gil, Hospital Central do Funchal, Funchal, Portugal
Background

Fabry’s Anderson disease (FAD) is a rare disorder that is highly undiagnosed worldwide. This entity is caused by alpha-galactosidase A gene (GLA) mutations. FAD, being a rare cause of end-stage renal disease (ESRD), accounts for less than 0,02% of all causes. The prevalence of FAD in Portugal is expected to be 1 in 833,000. Considering Madeira Island’s (MI) population of about 250.000, one would not ponder more than one case, but little is known about FAD. Nevertheless, preliminary studies taking course point out to an increased genetic pool.

Methods

Screening of FAD is being performed among dialysis patients in MI. Alpha galactosidase A (AGAL) activity is obtained by a blood spot test. Male patients with decreased AGAL activity are tested for genetic mutations. Female patients are tested for genetic mutations regardless of AGAL activity. The diagnosis is confirmed by the presence of the mutations in the GLA gene. These patients also have lyso-Gb3 measurements. The pathogenicity is determined according to Annual Clinical Meeting Genetics (ACMG).

Results

Among 72 patients tested, we found 4 different mutations in 4 different families, all with distinctive pathogenicity. Following studies in those families revealed 10 additional cases and we are still testing other members. Two of these families have a previously described pathogenic mutation, c.937G>T (pAsp313Tyr) in family 1 with 2 affected females and c.870G>C (pMet290Ile) in family 2 with 1 affected male and 5 affected females. Family 3 has a c.352C>T (pArg118Cys) mutation labelled as pathogenic although with conflicting reports in several studies. Curiously, we discovered a novel mutation in family 4 never reported before, referring to exon 4 of GLA gene, c.580A>G (p.Thr194Ala). Further evaluations of clinical findings suggest this mutation to be pathogenic.

Conclusion

Testing in dialysis patients and other members of identified families in MI will probably result in higher prevalence of FAD. These results are clearly above what would be expected from published previous studies. The reasons are unknown and further prompt investigation is required. Additional evaluation of affected patients will help understand the pathogenic implications.

Funding

  • Commercial Support