Functional and pharmacological evaluation of novel GLA variants in Fabry disease identifies six (two de novo) causative mutations and two amenable variants to the chaperone DGJ

Lorenzo Ferri, Duccio Malesci, Antonella Fioravanti, Gaia Bagordo, Armando Filippini, Anna Ficcadenti, Raffaele Manna, Daniela Antuzzi, Elena Verrecchia, Ilaria Donati, Renzo Mignani, Catia Cavicchi, Renzo Guerrini, Amelia Morrone

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Allelic heterogeneity is an important feature of the GLA gene for which almost 900 known genetic variants have been discovered so far. Pathogenetic GLA variants cause alpha-galactosidase A (α-Gal A) enzyme deficiency leading to the X-linked lysosomal storage disorder Fabry disease (FD). Benign GLA intronic and exonic variants (e.g. pseudodeficient p.Asp313Tyr) have also been described. Some GLA missense variants, previously deemed to be pathogenetic (e.g. p.Glu66Gln and p.Arg118Cys), they have been reclassified as benign after re-evaluation by functional and population studies. Hence, the functional role of novel GLA variants should be investigated to assess their clinical relevance. Results: We identified six GLA variants in 4 males and 2 females who exhibited symptoms of FD: c.159C>G p.(Asn53Lys), c.400T>C p.(Tyr134His), c.680G>C (p.Arg227Pro), c.815A>T p.(Asn272Ile), c.907A>T p.(Ile303Phe) and c.1163_1165delTCC (p.Leu388del). We evaluated their impact on the α-Gal A protein by bioinformatic analysis and homology modelling, by analysis of the GLA mRNA, and by site-directed mutagenesis and in vitro expression studies. We also measured their responsiveness to the pharmacological chaperone DGJ. Conclusions: The six detected GLA variants cause deficient α-Gal A activity and impairment or loss of the protein wild-type structure. We found p.Asn53Lys and p.Ile303Phe variants to be susceptible to DGJ.

Original languageEnglish
Pages (from-to)25-33
Number of pages9
JournalClinica Chimica Acta
Volume481
DOIs
Publication statusPublished - Jun 1 2018

Keywords

  • 1-Deoxygalactonojirimycin
  • Atypical variants
  • De novo mutation
  • DGJ
  • Lipofectamine
  • Site-directed mutagenesis

ASJC Scopus subject areas

  • Biochemistry
  • Clinical Biochemistry
  • Biochemistry, medical

Fingerprint Dive into the research topics of 'Functional and pharmacological evaluation of novel GLA variants in Fabry disease identifies six (two de novo) causative mutations and two amenable variants to the chaperone DGJ'. Together they form a unique fingerprint.

Cite this