Levels of Lyso GL-1 in Gaucher and Lyso GL-3 in Fabry patients from India: Diagnostic aids for these lysosomal storage disorders.

BACKGROUND & AIMS: Lysosomal storage disorders (LSDs) remain a significant cause of morbidity in the Indian population and treatment is largely out of reach for most patients. Although data on enzymatic and molecular diagnosis of Gaucher disease (GD) and Fabry disease (FD) in Indian patients are available, the present study intended to establish the pathogenic levels of Lyso GL-1 and Lyso GL-3 in patients of GD and FD respectively as diagnostic aids. MATERIALS AND METHODS: From 2017 to 2019, ninety confirmed Gaucher cases (by enzymatic and molecular analysis) were tested for chitotriosidase (fluorometrically) and Lyso GL-1 (LC-MS/MS) and ten confirmed Fabry cases were analyzed for Lyso GL-3 (LC-MS/MS). RESULTS: Lyso GL-1 (median: 685.5 ng/mL, cut-off: 14) and Lyso GL-3 (median: 75.6 ng/mL, cut-off: 3.5) were found to be elevated in all enzymatically deficient patients of GD and FD respectively, however, no specific trend was observed between the levels of these biomarkers and the pathogenic variant(s) present in the patients of these disorders. CONCLUSIONS: This is the first report on Lyso GL-1 and Lyso GL-3 levels in Indian patients of GD and FD respectively. These results will be useful for early diagnosis to improve management of these LSDs.

Lysosomal storage disorders: Novel and frequent pathogenic variants in a large cohort of Indian patients of Pompe, Fabry, Gaucher and Hurler disease.

OBJECTIVES: Diagnosis of lysosomal storage disorders (LSDs) remains challenging due to wide clinical, biochemical and molecular heterogeneity. The study applies a combined biochemical and genetic approach to diagnose symptomatic Indian patients of Pompe, Fabry, Gaucher and Hurler disease to generate a comprehensive dataset of pathogenic variants for these disorders. DESIGN & METHODS: Symptomatic patients were biochemically diagnosed by fluorometric methods and molecular confirmation was carried out by gene sequencing. Genetic variants were analyzed according to the ACMG/AMP 2015 variant interpretation guidelines. RESULTS: Amongst the 2181 suspected patients, 285 (13%) were biochemically diagnosed. Of these, 22.5% (64/285) diagnosed with Pompe disease harboured c.1933G>A, c.1A>G, c.1927G>A and c.2783G>C as common and 10 novel pathogenic variants while 7.4% (21/285) patients diagnosed with Fabry disease carried c.851T>C, c.902G>A, c.905A>C and c.1212_1234del as frequent disease-causing variants along with 7 novel pathogenic variants. As many as 48.4% (138/285) patients were diagnosed with Gaucher disease and had c.1448T>C as the most common pathogenic variant followed by c.1342G>C and c.754T>C with 7 previously unreported disease-causing variants and in the 21.7% (62/285) diagnosed cases of Hurler disease, c.1469T>C, c.754delC c.568_581del and c.1898C>T were identified as the most common causative variants along with 21 novel pathogenic variants. CONCLUSION: This comprehensive data set of disease-causing frequent and novel pathogenic variants reported for the first time in such a large patient cohort for each of these four LSDs from the Indian sub-continent, along with their biochemical and clinical spectrum will contribute towards providing definitive diagnosis and treatment, identifying carrier status, as well as in counselling prenatal cases to reduce the morbidity and mortality associated with these disorders.

Inherited metabolic disorders: prenatal diagnosis of lysosomal storage disorders.

OBJECTIVE: To offer accurate prenatal diagnosis of lysosomal storage disorders in early pregnancy. METHOD: Prenatal enzymatic diagnoses of Gaucher, Fabry, Pompe, Niemann Pick A/B, Tay Sach, Sandoff, GM1, mucoplysaccharidoses, Wolman, Krabbe, Metachromatic leukodystrophy and Batten diseases were made in uncultured chorionic villi samples by fluorometric/spectrophotometric methods. RESULTS: Of 331 prenatal enzymatic diagnosis, 207 fetuses (67%) were normal and 124 (37%) were affected. The interpretation of affected, normal and carrier fetuses was done using their respective reference ranges as well as % enzyme activity of normal mean. The prenatal molecular confirmation was feasible in 43 biochemically diagnosed fetuses. Of the 207 normal reported fetuses, post natal enzymatic confirmation was done in 23 babies, clinical status of another 165 babies was assessed as unaffected via questionnaire on telephone and 19 were lost to follow-up. In affected pregnancies, 123 opted for termination of which 44 were confirmed enzymatically after abortion. A single false positive was determined to be a carrier by prenatal mutation analysis and carried to term. CONCLUSION: We recommend uncultured chorionic villi for reliable prenatal enzymatic diagnosis of various lysosomal storage disorders on account of the low rate of false positive (0.5%) and false negative (2.2%) results.

Effect of endosulfan and malathion on lipid peroxidation, nitrite and TNF-alpha release by rat peritoneal macrophages.

Endosulfan and malathion are organochlorine and organophosphate insecticides, respectively. The toxicity of both the insecticides are well known on non-target organisms. Both endosulfan and malathion are reported to suppress humoral as well as cellular immune responses. We investigated the possible effect of both these insecticides on lipid peroxidation, nitrite production and TNF-alpha generation in rat peritoneal macrophages under in vitro conditions. Rat peritoneal cells were collected and cultured with or without insecticides and relevant stimulants for lipid peroxidation, generation of nitric oxide and TNF-alpha. FeSO(4) was used as an inducer for lipid peroxidation and LPS was used to induce nitric oxide synthase and release of TNF-alpha. Lipid peroxidation was assayed by estimating MDA; nitric oxide was determined by estimating nitrite and TNF-alpha by using an assay kit in culture supernatants. Both endosulfan and malathion had no effect on lipid peroxidation. Endosulfan did not have any influence on nitrite production, but suppressed the LPS-induced TNF-alpha generation. Malathion, however, showed a direct suppression on nitrite production and suppression of LPS-induced TNF-alpha generation. This study suggests that functional aberrations of macrophages may contribute significantly to the immunomodulation reported for these insecticides.