Gaucher disease: expression and characterization of mild and severe acid β-glucosidase mutations in Portuguese type 1 patients

Abstract

Type 1 Gaucher disease (GD), the most prevalent lysosomal storage disease, results from the deficient activity of acid -glucosidase. Molecular analysis of 12 unrelated Portuguese patients with type 1 GD identified three novel acid -glucosidase mutations (F109V, W184R and R395P), as well as three previously reported, but uncharacterized, lesions (R359Q, G377S and N396T). The type 1 probands were either heteroallelic for the well-characterized common lesion, N370S, and the F109V, W184R, R359Q or N396T lesions or homoallelic for the G377S or N396T mutations. Expression of the W184R, R359Q, and R395P mutations revealed very low specific activities based on cross-reacting immunologic material (CRIM SAs of 0.0004, 0.016 and 0.045, respectively), consistent with their being found only in type 1 patients who had a neuroprotective N370S allele. In contrast, the F109V, G377S and N396T alleles had significant acid -glucosidase activity (CRIM specific activities of 0.15, 0.17, 0.14, respectively), in agreement with their being mild type 1 alleles. Thus, these studies identified additional acid -glucosidase mutations in the Portuguese population and demonstrated that the G377S and N396T mutations were neuroprotective, consistent with the mild clinical phenotypes of the type 1 patients who were homoallelic for the G377S and N396T lesions. European Journal of Human Genetics (2000) 8, 95-102.

X-ray Structure of Human Acid-β-Glucosidase Covalently Bound to Conduritol-B-Epoxide

“…The flexibility of these loops is crucial for the catalytic activity of the glycosyltransferases (27). In GlcCerase, the role of one of the two surface loops in governing access to the active site is supported by the reduced affinity of GlcCerase for CBE in various GlcCerase mutations, such as V394L (4), R395P, and N396T (20), although V394L also displays reduced thermostability and reduced stability at low pH (4), implying a disruption of structural integrity that may result in rapid lysosomal degradation. Thus, loop mutations may both decrease the catalytic activity of GlcCerase and reduce its lysosomal enzyme concentration.…”

“…Analysis of the distribution of mutant forms of GlcCerase that cause Gaucher disease reveals a cluster of mutations in loop 2, including V394L (2), R395P (20), N396T (21), V398L/F (22,23), and D399N (24). In silico analysis of these mutants is consistent with either destabilization of the open conformation or stabilization of the closed conformation (Table III) 127 in the open conformation.…”

Newborn Screening for Lysosomal Storage Disorders in Hungary

“…In all three cases we were able to detect a compound heterozygosity for L483P, a mutation predisposing for a severe course of Gaucher disease, where early detection is of high importance (Montfort et al 2004). Furthermore, seven carriers for Gaucher disease were identified, the mutations c.1226 A>G (p.N409S) (Tsuji et al 1988) and c.1223 C>T (p.T408M) (Beutler et al 1996) occurring once and five times, respectively, and both linked to the type I of Gaucher disease (Amaral et al 2000;Miocić et al 2005;Nichols et al 2009). In addition, both c.1223 C>T (p.T408M) (Beutler et al 1996) and c.475 C>T (p.R159W) (Horowitz and Zimran 1994) have been proven to be connected with Parkinson's disease (Hodanová et al 1999;Amaral et al 2000;Mitsui et al 2009).…”

Consanguinity and founder effect for Gaucher disease mutation G377S in a population from Tabuleiro do Norte, Northeastern Brazil

“…The fact that the carriers and affected subjects identified in this study are descendents of Jewish immigrants from Cartaxo, Portugal (11), and that the mutation G377S has been observed in homozygosis in one Portuguese Sephardic Jewish patient suggests that the G377S mutation may be Sephardic in origin (16), although the gene frequency of this mutation is not significant among Jewish subjects (3,19).…”

“…The G377S mutation is the fourth most prevalent GD-related mutation in Spain (n = 25; 3.0%) (2) and the third most prevalent in both Portugal (n = 4; 7.4%) (16) and Brazil (n = 11; 2.2%) (14). Initially, it was believed to be neuroprotective owing to its mild effect, high residual enzyme activity and the fact that all known Portuguese homozygotes for G377S have type 1 GD (17).…”