Increased glycolipid storage produced by the inheritance of a complex intronic haplotype in the α-galactosidase A (GLA) gene.
BACKGROUND
Accumulation of galactosphingolipids is a general characteristic of Fabry disease, a lysosomal storage disorder caused by the deficient activity of α-galactosidase A encoded by the GLA gene. Although many polymorphic GLA haplotypes have been described, it is still unclear whether some of these variants are causative of disease symptoms. We report the study of an inheritance of a complex intronic haplotype (CIH) (c.-10C > T, c.369 + 990C > A, c.370-81_370-77delCAGCC, c.640-16A > G, c.1000-22C > T) within the GLA gene associated with Fabry-like symptoms and galactosphingolipid accumulation. We analysed α-Gal A activity in plasma, leukocytes and skin fibroblasts in patients, and measured accumulation of galactosphingolipids by enzymatic methods and immunofluorescence techniques. Additionally, we evaluated GLA expression using quantitative PCR, EMSA, and cDNA cloning.


RESULTS
CIH carriers had an altered GLA expression pattern, although most of the carriers had high residual enzyme activity in plasma, leukocytes and in skin fibroblasts. Nonetheless, CIH carriers had significant galactosphingolipid accumulation in fibroblasts in comparison with controls, and also glycolipid deposits in renal tubules and glomeruli. EMSA assays indicated that the c.-10C > T variant in the promoter affected a nuclear protein binding site.


CONCLUSIONS
Thus, inheritance of the CIH caused an mRNA deregulation altering the GLA expression pattern, producing a tissue glycolipid storage.
Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Zaragoza, Spain. gervas.j@gmail.com.|Translational Research Unit, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Miguel Servet University Hospital, Zaragoza, Spain. gervas.j@gmail.com.|Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain. gervas.j@gmail.com.|Biochemistry and Molecular and Cellular Biology Department, Universidad de Zaragoza, Zaragoza, Spain. gervas.j@gmail.com.
Javier
J
Gervas-Arruga
Translational Research Unit, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Miguel Servet University Hospital, Zaragoza, Spain. jorgecebollasanz@gmail.com.|Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain. jorgecebollasanz@gmail.com.|Biochemistry and Molecular and Cellular Biology Department, Universidad de Zaragoza, Zaragoza, Spain. jorgecebollasanz@gmail.com.
Jorge J
JJ
Cebolla
Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Zaragoza, Spain. mpirun.uit@gmail.com.|Translational Research Unit, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Miguel Servet University Hospital, Zaragoza, Spain. mpirun.uit@gmail.com.|Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain. mpirun.uit@gmail.com.|Biochemistry and Molecular and Cellular Biology Department, Universidad de Zaragoza, Zaragoza, Spain. mpirun.uit@gmail.com.
Pilar
P
Irun
Molecular Biology Department, Cantabria University and IFIMAV, Santander, Spain. javier.perez@unican.es.
Javier
J
Perez-Lopez
Anatomic Pathology Department, Miguel Servet University Hospital, Zaragoza, Spain. lplaza@salud.aragon.es.
Luis
L
Plaza
Neurology Department, Miguel Servet University Hospital, Zaragoza, Spain. jcrochebueno@hotmail.com.
Jose C
JC
Roche
Neurology Department, Miguel Servet University Hospital, Zaragoza, Spain. jcapablo@gmail.com.
Jose L
JL
Capablo
Molecular Biology Department, Cantabria University and IFIMAV, Santander, Spain. josecarlos.rodriguez@unican.es.
Jose C
JC
Rodriguez-Rey
Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain. mpocovi@unizar.es.|Biochemistry and Molecular and Cellular Biology Department, Universidad de Zaragoza, Zaragoza, Spain. mpocovi@unizar.es.
Miguel
M
Pocovi
Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Zaragoza, Spain. giraldocastellano@gmail.com.|Translational Research Unit, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Miguel Servet University Hospital, Zaragoza, Spain. giraldocastellano@gmail.com.|Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain. giraldocastellano@gmail.com.
Pilar
P
Giraldo
D000328:Adult; D000368:Aged; D000483:Alleles; D002460:Cell Line; D004789:Enzyme Activation; D000795:Fabry Disease / Q000235:genetics / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D056726:Genetic Association Studies; D005838:Genotype; D006017:Glycolipids / Q000378:metabolism*; D006239:Haplotypes; D006801:Humans; D007438:Introns; D007962:Leukocytes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D050199:Podocytes / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D022821:RNA Splice Sites; D000519:alpha-Galactosidase / Q000097:blood / Q000235:genetics* / Q000378:metabolism
D006017:Glycolipids; D022821:RNA Splice Sites; C576330:GLA protein, human; D000519:alpha-Galactosidase