Lysosomal Storage Disorders in Indian Children with Neuroregression Attending a Genetic Center.

Objective: To study the etiology of neuroregression in children having deficiency of the lysosomal enzymes. Design: Review of medical records. Setting: Specialized Genetic Center. Participants: 432 children aged 3 mo-18 y having regression in a learned skill, selected from 1453 patients referred for diagnostic workup of various Lysosomal storage disorders (LSDs). Methods: Plasma chitotriosidase, quantitative and qualitative glycosaminoglycans, and mucolipidosis-II/II screening followed by confirmatory enzyme study using specific substrate was carried out; Niemann-Pick disease Type-C was studied by fillipin stain method on skin fibroblasts. Results: Total 309 children (71.5%) were diagnosed with different lysosomal storage disorders as the underlying cause of neuroregression. Plasma chitotriosidase was raised in 82 of 135; 64 (78%) of these had various LSDs. 69 out of 90 cases showed high excretion of glycoaminoglycans, and 67 (97.1%) of these were confirmed to have enzyme deficiency for various mucoplysaccharide disorders. While 3/90 children with positive I-cell screening had confirmed mucolipidosis-II/III disease. Among all, glycolipid storage disorders were the most common (50.2%) followed by mucopolysaccharidosis (MPS) (21.7%) and sulphatide degradation defect (17.5%). Neuronal ceroid lipofucinosis-1 & 2 (7.4%), mucolipidosis-II/III (1%), Sialic acid storage disorder (1%), Niemann-Pick disease type-C (1%) and Fucosidosis (0.3%) were observed with less frequency. Most common phenotypes in all subjects were cherry red spot (18.5%), hepatosplenomegaly (17.9%), coarse facies (15%), seizures (13.1%) and skeletal abnormalities (12.14%). Conclusions: Lysosomal storage disorders are considered to be one of the common causes in children with regression in learned skill, dysmorphic features and cherry red spot. Among these, glycolipid storage disorders are the most common, followed by mucopolysaccharidosis.

Chromosomal abnormalities in couples with repeated fetal loss: An Indian retrospective study.

BACKGROUND: Recurrent pregnancy loss is a common occurrence and a matter of concern for couples planning the pregnancy. Chromosomal abnormalities, mainly balanced rearrangements, are common in couples with repeated miscarriages. PURPOSE: The purpose of this study is to evaluate the contribution of chromosomal anomalies causing repeated spontaneous miscarriages and provide detailed characterization of a few structurally altered chromosomes. MATERIALS AND METHODS: A retrospective cytogenetic study was carried out on 4859 individuals having a history of recurrent miscarriages. The cases were analyzed using G‑banding and fluorescence in situ hybridization wherever necessary. RESULTS: Chromosomal rearrangements were found in 170 individuals (3.5%). Translocations were seen in 72 (42.35%) cases. Of these, reciprocal translocations constituted 42 (24.70%) cases while Robertsonian translocations were detected in 30 (17.64%) cases. 7 (4.11%) cases were mosaic, 8 (4.70%) had small supernumerary marker chromosomes and 1 (0.6%) had an interstitial microdeletion. Nearly, 78 (1.61%) cases with heteromorphic variants were seen of which inversion of Y chromosome (57.70%) and chromosome 9 pericentromeric variants (32.05%) were predominantly involved. CONCLUSIONS: Chromosomal analysis is an important etiological investigation in couples with repeated miscarriages. Characterization of variants/marker chromosome enable calculation of a more precise recurrent risk in a subsequent pregnancy thereby facilitating genetic counseling and deciding further reproductive options.

Clinical and Molecular Characterization of Patients with Gross Hypotonia and Impaired Lower Motor Neuron Function.

Spinal muscular atrophy (SMA) represents the second most common fatal autosomal recessive disorder after cystic fibrosis. Due to the high carrier frequency, the burden of this genetic disorder is very heavy in developing countries like India. The aim was to study the clinical and molecular characteristics of patients suspected with SMA. It was a cross sectional study of 105 cases from January 2008 to August 2012. Patients’ demographic and presenting features and PCR findings were noted. 65 (62%) cases had a confirmed diagnosis of SMA. Werdnig Hoffman disease (SMA type I) was the commonest variant seen in 34 (52.3%) children. Molecular analysis demonstrated deletion of both exon 7 and 8 of SMN1 gene in 83.1% of cases.

Umbilical cord blood: Current status & promise for the future.

Umbilical cord blood (UCB) has been shown to be a suitable source of haematopoietic stem cells (HSCs) for haematopoietic reconstitution. An increase in the number of UCB transplants indicates an expansion of utility in a broad spectrum of disease conditions. Along with the advantages, UCB also has limitations, and hence several investigators are working to further optimize UCB for this use. Beyond haematopoietic transplantation, additional potential applications of UCB include immunotherapy, tissue engineering and regenerative medicine. UCB banking has improved with time largely due to involvement of professional organizations and their published standards. However, accreditation of these organizations remains voluntary, and in India three of ten banks are public with the remaining being private. Only one public and one private bank are American Association of Blood Banks (AABB) accredited in India. Government agencies need to provide regulatory and safety oversight, which is lacking in serveral countries. Public policy regarding UCB is in its infancy throughout most of the world. Ethical issues, including access to UCB banking and use as therapy for diseases other than haematological and metabolic disorders are in the early phase of trials and remain speculative.

Supernumerary Marker Chromosome in a Child with Microcephaly and Mental Retardation.

A de novo supernumerary marker chromosome (SMC) was identified in a 13- month-old girl who presented with microcephaly and mild mental retardation. On further characterization by oligo-nucleotide array-comparative genomic hybridization [array-CGH], the SMC was confirmed to be 18p.

Plasma chitotriosidase activity in children with lysosomal storage disorders.

Chitotriosidase (ChT) is an enzyme that is selectively activated in tissue macrophage. This property of ChT makes it a potential marker for many disease process and prognostication. Present study has been carried out to know the significance of ChT as a screening marker in lysosomal storage disorders (LSDs) where tissue macrophage activation is commonly observed due to accumulation of substrate in various organs of the body. Study comprises of 20 healthy children in the age range of 10 days to 5 yrs and 56 children in the age range of 2.5 months to 13 yrs with regression of milestones, skeletal dysplasia, neuroregression and hepatosplenomegaly were selected for plasma ChT who had confirmed LSDs as carried out by specific lysosomal enzyme study from the leukocytes or fibroblasts. Plasma ChT was 55.21 ± 20.81 nmol/ml /hr in twenty healthy age matched controls. Plamsa ChT level was 42.88 to 79.78 nmol/ml/hr in thirteen of 56 (23.21%) children with LSDs like Morquio- B, Pompe, Metachromatic leucodystrophy (MLD), Sandhoff and Niemann-Pick disease type C (NPD-C). While in 43 (76.78%) children it was in the range of 213.74 to 23,511.40 nmol/ml/hr. who had LSDs like Morquio-B, Sly syndrome, MLD, GM2 Gangliosidosis, NPD-A/B and Gaucher disease (GD). Marked elevated ChT (4,000 to 23,511 nmol/ml/hr) was observed in all cases of GD (n=7) and NDP-A/B. It can be concluded from the present study that moderately raised activity of ChT can be utilized as a positive predictive test for certain LSD’s. Those with marked elevated ChT have confirmed GD or NPD-A/B making it a strong screening marker for this group of diseases.

Association of HLA-B*1502 allele and carbamazepine-induced Stevens-Johnson syndrome among Indians.

Background: Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis are severe cutaneous reactions caused by certain drugs, including antiepileptic carbamazepine. A strong association has been reported between human leucocyte antigen (HLA)-B*1502 and carbamazepine-induced SJS in Han Chinese patients. European studies suggested that HLA-B*1502 is not a universal marker but is ethnicity-specific for Asians. Aim: To study the association between HLA-B*1502 and carbamazepine-induced SJS in Indian patients. Methods: Eight individuals who fulfilled the diagnostic criteria of SJS induced by carbamazepine were identified and HLA-B molecular typing was performed. HLA-B genotyping was carried out by polymerase chain reaction using sequence-specific primers. Results: Out of eight patients studied for genotype, six patients were found to have the HLA-B*1502 allele. Conclusion: This study suggests an association between HLA-B*1502 and carbamazepine-induced SJS in Indian patients.

Niemann-Pick type C disease.

A 4-year-old Afghan girl born to consanguineous parents presented with progressive neurological regression and hepatomegaly noticed after one year of age.The child had hypotonia, repeated unexplained falls and facial dyskinesia. Bone marrow examination revealed presence of storage cells suggestive of Gauchers or Niemann Pick. Confirmatory study by lysosomal enzyme from leucocytes was normal for beta-Glucosidase and sphingomyelinase specific for Gauchers and Niemann Pick type A or B respectively. Further study was carried out on cultured skin fibroblasts in lipid deficient medium using filipin stain which showed presence of dark punctate granules confirming the diagnosis of Neimann-Pick type C, a rare autosomal recessive disorder.

Cytogenetic analysis of Down syndrome in Gujarat.

During 1995 to 2006, 382 cases clinically suspected for Down syndrome were investigated for cytogenetic study. Free trisomy 21 constituted 84.8% of cases, translocation 8.9%, mosaic 3.9% and in 2.4% cases regular T21 was associated with structural or numerical changes. Translocation was parentally inherited in 26.5% cases and maternal transmission was twice as common as paternal. Males were more pronounced to be affected than females in all the groups. 91.6% of DS babies were born to younger mothers (20-35 yr) compared to 8.4% in elderly mothers (>35 yr).

Ring chromosome 9 in a dysmorphic child.

Ring chromosome is a rare genetic disorder observed in the children with variable clinical presentation and phenotype. Among several ring formation, individuals with r(9) generally have less distinct clinical features. An eight-mth-old boy, presenting with broad and dark eyebrows with protruding tongue, microcephaly, short stature and failure to thrive was found to have ring chromosome 9. 46,X,inv(Y),r(9)(p24q34). This shows that karyotype study is an essential integral investigation in the management of dysmorphic child.

A three way complex translocation (4; 9; 22) in two patients with chronic myelocytic leukemia.

Chronic myeloid leukemia (CML) is genetically characterized by the reciprocal translocation of chromosome 9 and 22, t(9;22)(q34;q11) which results in the fusion of BCR/ABL gene observed on the derivative chromosome 22 called Philadelphia (Ph') chromosome. About 5-8% of Philadelphia positive patients with CML show various complex translocations involving third chromosome in addition to chromosome 9 and 22. In present report we discuss two cases with CML referred at our centre. At the time of initial diagnosis and after 9 months of treatment, one of the patients showed 100% presence of Philadelphia positive in bone marrow culture. During follow-up in an accelerated state, his cytogenetic study revealed a complex translocation (4;9;22)(q25;q34;q11) along with an additional Philadelphia and marker chromosome. The second patient showed a complex (4;9;22)(q25;q34;q11) translocation at the time of diagnosis. He was on hydroxyurea and his follow-up cytogenetic study after the course of chemotherapy showed no changes. Further confirmation of complex translocation was done by FISH study using bcr/abl and whole chromosome 9 probes. Though the additional genes involved in complex variant Ph' rearrangements have not been characterized, both patients are healthy till 3 to 5 years of initial diagnosis. This could be attributed to the benign effect resulted from reciprocal translocation with no loss or gain of the genetic material.

Lysosomal storage disorders.

This study was conducted to assess the variability of clinical expression of Lysosomal storage disorders (LSDs) and the selection of specific enzyme investigation to reach the differential diagnosis. Initially 150 children in the age range of 15 days to 13 years were screened for common metabolic disorder and based on screening results, clinical signs and symptoms, 30 children(4 mo-12 yr) of these were selected for the leukocyte enzyme study. Of these 21 were confirmed to have LSDs. The most common disorder was GM2-gangliosidosis (47.61%, 10/21) followed by mucopolysaccharidosis (33.33%; 7/21). All showed variable phenotypic expression. Metachromatic leukodystrophy (MLD) was observed in 9.5% (2/21) of children with arylsulphatase A enzyme deficiency, while two children had shown pseudodeficiency of arylsulphatase A. One case each of galactosialidosis and GMI-gangliosidosis were observed. We conclude that children with developmental delay, seizures, dysmorphic features and organomegaly, with or without positive urinary screening for common metabolic disorders, need to be investigated further for LSDs.Variability of clinical expression is commonly observed in LSDs which require further confirmation by specific leukocyte enzyme study.

Gene polymorphism and folate metabolism: a maternal risk factor for Down syndrome.

The high birth frequency of Down syndrome (DS), trisomy 21 (T21), has been a subject of interest to the clinicians and researchers due to its complexity in phenotypic expression. In addition to the maternal age, identification of the mechanistic basis for T21 requires an understanding of the cellular-molecular events and other biochemical pathways that could promote maternal meiotic nondisjunction. Recent studies have linked the increased frequency of polymorphism of methylenetetrahydrofolate reductase (MTHFR, C677T) and methionine synthase gene (MTRR, A66G) in mothers with DS child. Based on evidence that abnormal folate and methyl metabolism can lead to DNA hypomethylation and abnormal chromosomal segregation, researchers have observed that mothers with mutation in MTHFR (C677T) and MTRR (A66G) gene have elevated levels of plasma homocysteine. This was found to be associated with a 2.6 to 2.9 fold increased risk of having child with DS compared to mothers without the mutation. Subsequent studies evaluating Italian, Irish, French, and Indian-Gujarati women could not demonstrate an association of MTHFR gene polymorphism in mothers with DS child. However, the Irish study did find an increased risk of DS associated with the MTRR polymorphism and an interactive effect of MTRR and MTHFR polymorphisms with increased risk. Interestingly, an increase in plasma homocysteine was found to be a risk factor for DS in several of the studies. Despite the differences, the published studies suggest a common theme of abnormal folate metabolism associated with increased risk of having a child with DS. These observations suggest that there seems to be a geographic variation in gene polymorphism and it could not be attributable to meiotic nondysjunction in all mothers with DS child but increased homocysteine in all different study group does suggest that there may be a gene-nutritional or gene-gene or gene-nutritional-environmental factors involved in increased frequency of meiotic nondisjunction which needs transnational and multinational study design.

Morquio-B syndrome (MPS-IV B) associated with beta-galactosidase deficiency in two siblings.

In the present article we describe two cases with Morquio-B syndrome characterized by beta-galactosidase deficiency in a Muslim family. They were found to have skeletal dysplasia, short stature and short trunk dwarfism with undetectable level of beta-galactosidase in leucocytes. Probands' sister who had no clinical signs of mucopolysaccharidosis was investigated and found to have normal levels of the enzyme. Mother was found to have a deficient activity of beta-galactosidase and father was not available for the study. Since mother was pregnant, prenatal study from chorionic cells was carried out to investigate beta-galactosidase activity in the chorionic villus. An intermediate level of beta-galactosidase activity was found in the chorionic villus cells suggesting a carrier status. The diversity and rarity of the study makes it worth presenting.