Israel Medical Association Journal

Abstract

Background: Gaucher disease is the most common lysosomal storage disorder and is caused by a deficiency of the enzyme glucocerebrosidase. Enzyme deficiency leads to the accumulation of undegraded substrates, mainly in cells of the monocyte/macrophage lineage, which is responsible for the clinical manifestations of the disease. To date, no study has attempted to identify the mutation spectrum of the glucocerebrosidase gene (GBA) in Slovak patients

Objectives: To identify mutations in 14 Slovak patients with confirmed glucocerebrosidase deficiency.

Methods: Using molecular genetics methods PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) and direct sequencing of coding region GBA we identified the spectrum of mutations in our patients.

Results: Five mutations (N370S, L444P, G377S, D409H and RecNciI) accounted for 75% of the mutant alleles. The remaining 25% were rare and probably individual mutations.

Conclusions: The mutational spectrum in our patients is similar to that observed in other European countries and corresponds to a Caucasian population, with N370S, L444P, RecNciI being the most common mutation. Interestingly, mutation G377S was more frequent in our patients as compared to other published data. The C4W, L96P, H311N, 745delG and 1127_1128delTT mutations are described here for the first time in Gaucher disease, contributing to the panel of published GBA mutations.  

Background: Gaucher disease is the most prevalent inherited disorder among Ashkenazi Jews (carrier frequency of about 6%) and six mutations account for about 96% of their mutant alleles. Two mutations, N370S and R496H, have been reported only in mildly affected or asymptomatic patients, Due to the rarity of R496H, it was recommended that it be excluded from screening programs. 

Objectives: To verify the frequency and trace the origin of Gaucher mutations in screened individuals whose Ashkenazi ethnicity was confirmed by the birthplace of their grandparents.

Methods: We conducted a retrospective analysis of the screened results for the period 2006–2011. Mutations were identified by restriction analysis, Tag-It^TM detection system, Pronto® diagnostic kit and Nanogen technology (NanoChip® 400).

Results: The heterozygote frequency of eight mutations was estimated in a cohort of 16,910 alleles. Two mutations, N370S and R496H, were the most frequent in our population. However, while the occurrence of N370S carriers was similar to other reports (1:19.4), that of R496H carriers was considerably elevated (1:207). Examination of the screened individuals' ethnicity showed a significant difference in the distribution pattern of the country of origin between the carriers of these two mutations.

Conclusions: The origin pattern differences between the two groups of heterozygotes might reflect a separate geographic region of introduction for various mutations. As a result, secondary subgroups could be formed within the Ashkenazi population. This might clarify the dissimilarities in the occurrence of R496H mutation reported by various centers. 

Background: With regard to ethnic predilections for Gaucher disease, the most common storage disorder, Ashkenazi Jews are at risk for the non-neuronopathic form (type I), Norbottnian Swedes are at risk for the sub-acute neuronopathic form (type III), and perhaps Arabs are at risk for the very rare cardiac variant of the sub-acute neuronopathic form (type IIIc) for which there is a relatively tight genotype-phenotype correlation. Type II, the acute infantile form, being the rarest form, has not been associated with any ethnic predilection.

Objectives: To examine whether Arab ethnicity influences the Gaucher phenotype.

Methods: We reviewed the records of all Arab patients in a referral clinic of 586 patients in Israel.

Results: There were 46 patients (7.8%) of Arab ethnicity: 23 (50%) had type I disease, 16 (34.8%) had type IIIc disease, 4 (8.7%) had type IIIb disease, and 3 (6.5%) had type II disease. Type IIIc disease was characterized by genotype-phenotype correlation with homozygosity for the D409H (1342C) mutation. All five Bedouin patients (10.9%) had the R48W (C259T) mutation on at least one allele.

Conclusions: For all genotypes, disease severity among Arab patients was relatively similar to that reported among other Caucasian patients. Apparently Arab ethnicity does not impact phenotypic expression in Gaucher disease in a unique manner. The predilection for type IIIc may be a result of consanguinity.
 

The Ashkenazi-Jewish population is at increased risk for several recessively inherited disorders. While some of the disorders have severe or fatal symptom manifestations, others, such as non-neuronopathic Gaucher disease, do not usually pose a serious, life-threatening illness. Many healthcare centers in Israel offer prenatal panel screening. Controversy exists over the inclusion of Gaucher disease in the panel screening, especially since Gaucher disease screening lacks prognostic reliability. Most screening participants do not discriminate between the specific tests in the panel and are unable to discern between severe, life-threatening diseases and those that are less severe and even treatable. By including screening for Gaucher in the panel screening program, there is risk of a "panel effect," leading to termination of a pregnancy positive for Gaucher disease, without sufficient knowledge and understanding of the disease. Increasing medical and public awareness and knowledge of the disease, its prognosis and treatment options may reduce the rate of under-informed abortions associated with prenatal screening of Gaucher disease.

Background: Gaucher disease results from the accumulation of glucosylceramide (glucocerebroside) in tissues of affected persons. Patients sharing the same genotype present with widely varying degrees of lipid storage and of clinical manifestations.

Objectives: To determine whether variation in the glucosylceramide synthase (UDPGlucose ceramide glucosyltransferase) gene, which encodes the enzyme that regulates the synthesis of glucocerebroside, could account for the variability and clinical manifestations.

Methods: Patients homozygous for the 1226G (N370S) mutation, the most common in the Ashkenazi Jewish population, were investigated. The exons and flanking sequences of the gene were sequenced using DNA derived from five very mild Gaucher disease patients and four patients with relatively severe Gaucher disease. Results: One polymorphism was found in the coding region, but this did not change any amino acids. Seven other polymorphisms were found in introns and in the 5' untranslated region. Some of these were single nucleotide polymorphisms; others were insertions. The mutations appear to be in linkage equilibrium and none were found with a significantly higher frequency in either severe or mildly affected individuals.

Conclusions: Mutations in the glucosylceramide synthase gene do not appear to count for the variability in expression of the common Jewish Gaucher disease mutation.
 

Background: Growth retardation in childhood was only recently recognized as a prominent feature of Gaucher disease type 1, but there are few data on both the pubertal development and the final outcome of growth and sexual maturation.

Objective: To investigate the natural pattern of growth and puberty in patients with Gaucher disease type 1 and the effect of splenectomy and enzyme replacement therapy.

Methods: We retrospectively analyzed growth and puberty in 57 patients with Gaucher disease type 1; 52 were followed since childhood and/or prepuberty and 42 have reached sexual maturity and final height. In the analysis we considered severity of disease, time of splenectomy, and start of enzyme replacement therapy.

Results: Deceleration of growth at age 3–5 years was observed in 30 of 57 patients followed since early childhood while untreated: height-SDS decreased from -0.34±0.42 at age 0–3 years to -1.93±0.95 (P<0.01) at age 7–10 years and was more pronounced with severe disease. A high prevalence (59.6%) of delayed puberty, which was more frequent with severe disease, was observed in 47 patients followed before and throughout puberty. No primary endocrine pathology was found. All patients, untreated as well as treated, with growth and pubertal delay had a spontaneous catch-up, achieved full sexual maturation, and most (83.3%) reached a final height within the range of parental height–standard deviation score. Splenectomy (partial and/or total) performed in 20 patients while still growing had a beneficial effect on growth, which was temporary in some and did not affect puberty. ERT improved growth in 11 patients who started therapy before puberty, as evidenced by a progressive increase in the height-SDS, and seemed to normalize the onset of puberty.

Conclusions: Growth retardation in childhood and delay of puberty are characteristic of Gaucher disease type 1 and are more frequent with severe disease. There is a spontaneous catch-up later in life and most patients reach a final height within their genetic growth potential. Enzyme replacement therapy apparently normalizes growth and possibly also the onset of puberty.

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ERT = enzyme replacement therapy

SDS = standard deviation score