Lysosomal storage disorders in Indian children with neuroregression attending a genetic center

Caries assessment and salivary microbial analysis in patients diagnosed with mucopolysaccharidosis

BACKGROUND AND OBJECTIVES

Mucopolysaccharidosis (MPS) is a group of lysosomal storage disorders that cause the deposition of polysaccharides in cells. This causes systemic and oral manifestations, which can be observed clinically and radiographically. The present study aimed to assess dental caries, the effect of salivary pH, and the change of microflora on teeth in patients diagnosed with MPS.

MATERIALS AND METHODS

The study included children affected with mucopolysaccharidosis (n = 50) and healthy children (n = 50) in the control group between 3 and 15 years of age. The pH of saliva and decayed, missing, and filled teeth/decayed extracted and filled teeth index were noted and recorded. For the microbial analysis, saliva was inoculated into blood agar, MacConkey agar, Candida CHROMagar, and Mitis Salivarius agar, then inspected for colony-forming units, which were counted and recorded based on the colony characteristics and gram staining.

STATISTICAL ANALYSIS

Intergroup comparison of the test parameters was done using the Mann-Whitney test. P < 0.05 was considered statistically significant.

RESULTS

The results showed significantly higher total microbial load (P = 0.00008), streptococcus viridans species (P = 0.00001), and Candida species (P = 0.0038) in the study group. The caries incidence was also higher in the study group for both primary (P = 0.0096) and permanent dentition (P = 0.0251), and salivary pH was more acidic (P = 0.00001) in the patients diagnosed with MPS.

INTERPRETATION AND CONCLUSION

Patients diagnosed with MPS have a higher microbial load, more acidic saliva, and subsequently, a higher caries incidence than normal healthy children. Hence, regular dental evaluation, prevention, and treatment must be integrated into their health-care regimen.

The Spectrum of Inherited Gray Matter Degenerative Brain Disorders (DBD) in Children: A Single-Center Study

Objectives

To study the clinical spectrum of inherited gray matter degenerative brain disorders (DBD) in children.

Methods

This cross-sectional study evaluated children up to 12 y of age, diagnosed with an inherited gray matter DBD in a tertiary care pediatric hospital between July 2019 and December 2020.

Results

A total of 314 children with progressive neuroregression were screened. Of these, 117 children with inherited gray matter DBD were included in the study. The clinic-based prevalence of DBD was 8.2%, and inherited gray matter DBD was 3.1%. The proportion of the inherited gray matter DBD was 37.3% among the overall DBD cases. Children were categorized into three groups based on the age at onset of disease: below 2 years (N = 57, 48.7%), between 2 and 5 years (N = 32, 27.3%), and between 6 and 12 years (N = 28, 23.9%). Based on the predominant cerebral structure involved, gray matter DBD were classified as cerebral gray matter disorders (53%), basal ganglia disorders (34.1%), and cerebellar disorders (12.8%). Overall, the most common disorders were Wilson disease (18%), neuronal ceroid lipofuscinosis (NCL) (17%), and neurodegeneration with brain iron accumulation (NBIA) (16%). The most common gray matter DBD in children <2 years of age were NBIA (n = 11), Rett syndrome (n = 11), and gangliosidoses (n = 10). NCL (n = 14) and ataxia telangiectasia (n = 6) were most common in the age group of 2-5 years. Wilson disease (n = 19) was the most common disorder in the age group of 6-12 years followed by NCL (n = 4) and NBIA (n = 3).

Conclusion

Our study highlights the burden and spectrum of gray matter DBD in children. The clinic-based prevalence of DBD was 8.2%, and of inherited gray matter DBD was 3.1%. The proportion of inherited gray matter DBD was 37.3% among the overall DBD cases. Wilson disease, NCL, and NBIA are the most common gray matter DBD in children. Timely diagnosis is important for the prevention of recurrence in subsequent pregnancies.

Lysosomal storage disorders: from biology to the clinic with reference to India

Lysosomal storage disorders (LSDs) are a group of seventy different metabolic storage diseases due to accumulation of substrate mainly in the form of carbohydrate, lipids, proteins, and cellular debris. They occur due to variant in different genes that regulate lysosomal enzymes synthesis, transport, and secretion. In recent years, due to an increased availability of various therapies to treat these disorders, and increased diagnostic tools, there has been an escalated awareness of LSDs. Due to heterogeneous population and various social reasons, India is likely to have a high frequency of LSDs. Therefore, to understand the burden of various LSDs, its molecular spectrum, and understanding the phenotype-genotype correlation, Indian Council of Medical Research (ICMR) and Department of Health Research (DHR), Government of India had set up a task force in the year 2015. It has resulted in identifying common LSDs, and founder variant for some of the storage disorders and molecular spectrum of various LSDs across the country. This review describes in detail the spectrum of LSDs, its molecular epidemiology and prevention in context to Indian population.

Genetic Evaluation of the Parents Following Demise of the Index Case: Report of a Family with Fucosidosis

It is common in obstetric practice to encounter couples who seek prenatal genetic counseling and testing in view of history of known or suspected genetic disorders in the previous offspring or in other family members. Recent advances in genetic testing techniques, especially the availability of the next-generation sequencing (NGS) technology, have greatly facilitated genetic evaluation of the proband and/or the consultand couple and enabled provision of accurate genetic counseling and prenatal genetic testing in such clinical scenarios. However, even in this era of NGS, comprehensive clinical history taking and detailed phenotype characterization through clinical examination and thorough perusal of available medical records, are very important and essential for accurate diagnosis, as reiterated by this report of a 30-year-old third gravida, who was referred for prenatal genetic counseling and testing, in view of history of death of the first offspring due to a suspected neurogenetic disorder. Retrospective clinical diagnosis for the deceased index child with the help of available medical records and reports, followed by relevant NGS-based clinical exome sequencing of the couple, helped to arrive at a definitive diagnosis of fucosidosis, based on which accurate prenatal genetic testing could be done.

Clinical and Genetic Spectrum of 50 Children with Inborn Errors of Metabolism from Central India

This is a single-center, retrospective analysis of children confirmed to have an inborn error of metabolism in the pediatric department of a teaching hospital in central India. Patients were categorized as acute encephalopathy, developmental delay/seizures, and neuroregression or organomegaly depending on their predominant phenotype. Of the 50 patients analyzed, the commonest group was lysosomal storage disorders in 13 (26%), followed by organic acidurias - 8 (16%), mitochondrial disorders - 5 (10%), urea cycle disorders, carbohydrate metabolism disorders, and amino acidopathies - 4 (8%) each, fatty acid oxidation defects and neurotransmitter deficiency disorders - 3 (6%) each, and miscellaneous (8%). Genetic variations were identified in 25 (50%). Acylcarnitine profiles and urine organic acids were diagnostic in 62.5% of children presenting as acute encephalopathy, exome sequencing in 55.5% of children with neuroregression, and specific enzyme assay in 83.3% of children with predominant organomegaly (83.3%). Children with developmental delay/seizures needed a wider range of tests.

Eye of the Tiger: Looking Beyond Neurodegeneration with Brain Iron Accumulation Disorders

The “eye-of-the-tiger” sign in brain magnetic resonance imaging (MRI) is typically associated with neurodegeneration with brain iron accumulation disorders, especially pantothenate kinase-associated neurodegeneration. However, very similar neuroimaging findings may be seen in other neurodegenerative disorders involving the basal ganglia. We report here a patient with fucosidosis who had MRI brain findings closely resembling the “eye-of-the-tiger” sign.

Tay-Sachs disease: a novel mutation from India

Lysosomal storage disorders or lipidoses are a wide spectrum of inherited diseases caused by deficiency of a specific lysosomal hydrolase. About 134 mutations have been described so far and this number is gradually increasing with newer mutations being reported. We report a 28-month-old child who presented to us with neurodevelopment regression, seizures and cherry red spot in both eyes. His hexosaminidase A enzyme activity was reduced and genetic testing revealed a homozygous novel variation in HEXA (hexosaminidase A) gene in the DNA sample of the patient.

Identification and characterization of 20 novel pathogenic variants in 60 unrelated Indian patients with mucopolysaccharidoses type I and type II

Mucopolysaccharidoses (MPS), a subgroup of lysosomal storage disorders, are caused due to deficiency of specific lysosomal enzyme involved in catabolism of glycosaminoglycans. To date more than 200 pathogenic variants in the alpha-l-iduronidase (IDUA) for MPS I and ∼500 pathogenic variants in the iduronate-2-sulphatase (IDS) for MPS II have been reported worldwide. The mutation spectrum of MPS type I and MPS type II disorders in Indian population is not characterized yet. In this study, we carried out clinical, biochemical, molecular and in silico analyses to establish the mutation spectrum of MPS I and MPS II in the Indian population. We conducted molecular analysis for 60 MPS-affected patients [MPS I (n = 30) (Hurler syndrome = 17, Hurler-Scheie syndrome = 13), and MPS II (n = 30) (severe = 18, attenuated = 12)] and identified a total of 44 [MPS I (n = 22) and MPS II (n = 22)] different pathogenic variants comprising missense, nonsense, frameshift, gross deletions and splice site variants. A total of 20 [MPS I (n = 14), and MPS II (n = 6)] novel pathogenic sequence variants were identified in our patient cohort. We found that 32% of pathogenic variants detected in IDUA were recurrent and 25% in MPS II. This is the first study revealing the mutation spectrum of MPS I and MPS II patients in the Indian population.