Mandakini Pradhan

Geographic and Ethnic Distribution of β-Thalassemia Mutations in Uttar Pradesh, India

We have studied the geographic and ethinic distribution of mutations in 376 subjects who were carriers of β-thalassemia, and identified the mutations in 365 chromosomes. The majority of the β-thalassemia carriers were of Uttar Pradesh (India) origin. Their pattern of mutations differed from the other states of India and from those families who had migrated from Pakistan. The frequency of the NS-I-5 (G→C) and 619 bp deletion mutations were 64.3 and 2.5%, respectively, among families originating from Uttar Pradesh, compared to a prevalence of 37.5 and 27.5%, respectively in the population of Pakistani immigrants. Of the 10 common Asian Indian mutations, only eight were observed in subjects studied from different parts of India. By use of the amplification refractory mutation system along with DNA sequencing techniques, the mutations were successfully identified in 97.1% of subjects, while 11 cases (2.9%) still remain to be characterized by single strand conformation polymorphism and sequencing analyses. The application of this knowledge has facilitated the successful implementation of the program of genetic counseling and prenatal diagnosis of β-tbalassemia, thus helping to avoid the birth of an affected child in India.

MTHFR 677C→T and 1298A→C Polymorphisms: Evaluation of Maternal Genotypic Risk and Association with Level of Neural Tube Defect

Background: Neural tube defects (NTDs) are common birth defects (1 in 1,000) leading to significant morbidity and mortality. Periconceptional folic acid supplementation helps in prevention of 70% of NTDs. Recently, polymorphisms in genes encoding enzymes of the folate pathway have been implicated in causation of NTDs. Since the closure of neural tube occurs at multiple sites, the etiology of defect at different sites may be different – which explains the failure of folic acid supplementation to prevent all NTDs. Methods: Molecular analysis of methylenetetrahydrofolate reductase polymorphisms was carried out using polymerase chain reaction and restriction enzyme digestion. We studied the association of these polymorphisms in mothers with a previous child with NTD and further refined the risk by stratification based on level of defect. Results: The frequency of 677C→T homozygotes was higher in mothers with a previous child with NTD than the controls (OR = 1.6 (0.38–6.7), 95% CI, p = 0.72) but the difference was statistically insignificant. There was a significant difference in frequency of T alleles among mothers with a previous child with a ‘lower’ type of defect compared to controls (OR = 2.15 (1.13–4.1), 95% CI, p = 0.02). We did not find any significant association of 1298A→C polymorphism with the level of NTDs. Conclusions: We conclude that in the North Indian population, the 677C→T allele of the MTHFR gene may be associated with the occurrence of a lower type of NTD. This points towards the differential role of thermolabile MTHFR at different sites of neural tube closure.

Fetal Left Ventricular Diverticulum Presenting as Dysrhythmia: Diagnosis and Management

Congenital diverticulum of the left ventricle is amalformation, often associated with midline thoraco-abdominal defects. Here we describe a case of isolated congenital left ventricular diverticulum that presented with an abnormal four-chamber view and fetal dysrhythmia on ultrasonography. Maternal digoxin therapy was started due to significant ventricular ectopy. Restoration of fetal sinus rhythm was achieved within 48 h. Serial fetal echocardiograms were performed every week, followed by a normal vaginal delivery at term. The child is surviving at 1 year of age.

Genotyping of alpha-thalassemia in microcytic hypochromic anemia patients from North India

Microcytic hypochromic anemia is a common condition in clinical practice and alpha-thalassemia has to be considered as a differential diagnosis. Molecular diagnosis of α-thalassemia is possible by polymerase chain reaction. The aim of this study was to evaluate the frequency of α-gene numbers in subjects with microcytosis. In total, 276 subjects with microcytic hypochromic anemia [MCV<80fl; MCH<27pg] were studied. These include 125 with thalassemia trait, 48 with thalassemia major, 26 with sickle-cell thalassemia, 15 with E beta-thalassemia, 40 with iron-deficiency anemia, 8 with another hemolytic anemia, and 14 patients with no definite diagnosis. Genotyping for −α3.7 deletion, −α4.2 deletion, Hb Constant Spring, and α-triplications was done with polymerase chain reaction. The overall frequency of −α3.7 deletion in 276 individuals is 12.7%. The calculated allele frequency for α-thalassemia is 0.09. The subgroup analysis showed that co-inheritance of α-deletion is more frequent with the sickle-cell mutation than in other groups. We were able to diagnose 1/3 of unexplained cases of microcytosis as α-thalassemia carriers. The α-gene mutation is quite common in the Indian subcontinent. Molecular genotyping of α-thalassemia helps to diagnose unexplained microcytosis, and thus prevents unnecessary iron supplementation.

Status of HFE mutation in thalassemia syndromes in north India

Hereditary hemochromatosis is an autosomal recessive and most commonly inherited single gene disorder among Caucasians, with a prevalence of 5 per 1,000 and a carrier frequency of 1 in 10. Two point mutations were described and are referred as C282Y and H63D. In the present study, we have analyzed 729 north Indian samples for C282Y and H63D mutations. Of these, no allele of the C282Y mutation was seen, while 3 homozygous and 43 heterozygous for the H63D mutation were seen in the patients of thalassemia group. However, 47 cases were found heterozygous for the H63D mutation among the normal groups (11.16%).

A novel Indian β‐thalassemia mutation in the CACCC box of the promoter region

Abstract:  This is the first report of a previously undescribed mutation in Indian subjects of the CACCC box of promoter region for β‐globin, which in combination with a common mutation produces thalassemia major in the offspring of the family.

Ferroportin (SLC40A1) gene in thalassemic patients of Indian descent

To the Editor: Hemochromatosis is a progressive iron overload disorder that is more prevalent among north European population. The Online Mendelian Inheritance in Man database currently lists four types of hereditary hemochromatosis, each caused by mutations involving different genes (1). Ferroportin is the third protein identified as a site of defect in patients with hemochromatosis. Recent molecular basis of ferroportin-linked hemochromatosis suggested the central role of the hepcidin–ferroportin interaction in regulating iron homeostasis (2). Different types of mutations in ferroportin were described causing type IV (autosomal dominant) hemochromatosis. Montosi et al. (3) determined linkage of autosomal dominant hemochromatosis to 2q32 and demonstrated a missense mutation in the ferroportin gene (SLC40A1): a GCC to GAC change resulting in an A77D substitution. In India, thalassemia is the commonest cause of iron overload and hereditary hemochromatosis is very rare. The data on prevalence of mutations in HFE gene in Indian population are limited (4, 5). High-iron overload patients of thalassemia major and liver cirrhosis were evaluated for ferroportin gene mutations and other modifier genes of iron homeostasis. In this study, we screened for C282Y, H63D, ferroportin (A77D), transferrin (Y250X), hepcidin (C70R) and hemojuvelin (G320V) mutations in 147 thalassemia major patients and 65 cirrhotic patients. Sixty-five cirrhotic patients of various etiologies with normal iron status were included in the study as a control group. Informed written consent was obtained from all subjects and ethical clearance from the institute was taken to conduct this study. The genotype for A77D mutation was screened as described with slight modifications in PCR conditions (3). Two of the 147 thalassemia major patients were heterozygous for A77D mutation and one patient was homozygous for A77D mutation. In the control group, there was no mutant allele. The allele frequency in this population is calculated to be 0.012. Allele frequency of the H63D is 9.1. No mutations were identified in C282Y, transferrin (Y250X), hepcidin (C70R) and hemojuvelin (G320V). Mutations in the ferroportin (IREG1, SLC40A1) result in hemochromatosis type IV, a disorder with a dominant genetic pattern of inheritance and heterogeneous clinical presentations (2, 6). Ferroportin 1 plays key role in two different aspects of iron homeostasis: absorption of dietary iron by duodenal enterocytes and release of iron from body stores by reticuloendothelial cells. The heterogeneous clinical presentation in ferroportin mutations is due to differential involvement of theses two functions. Macrophages are involved in recycling of the iron from senescent erythrocytes. The reduction of iron efflux from macrophages leads to iron accumulation in the macrophages and reticuloendothelial organs with high serum ferritin level and low to normal transferrin saturation. It has been shown that A77D mutation in ferroportin has much larger reticuloendothelial iron stores than other forms of hemochromatosis. Interestingly, iron overload in thalassemia is primarily due to increased reticuloendothelial iron from senescent erythrocytes. Coinheritance of thalassemia with ferroportin mutation may aggravate the iron overload and may require more aggressive therapies. Moreover, ferroportin mutations can cause anemia that will modify the thalassemic phenotype. In our case, the effect of the mutation on iron overload is difficult to predict since the patient with the homozygous mutation recently started transfusion therapy. The other two heterozygous patients had high serum ferritin. However, multiple factors may contribute to iron overload in transfusion-dependent thalassemia major. Interaction of C282Y and H63D mutations with thalassemia is well studied. However, interaction of ferroportin mutations with thalassemia requires further studies. The literature on prevalence of hemochromatosis mutations in the Indian population is very scanty. C282Y mutation was not reported from India,

Genetics of Bleeding Disorders

Abstract Genetic bleeding disorders form an important presentation among various genetic disorders occurring in children. A prevalence of 6 per 100,000 population has been reported in India. Bleeding disorders constitute a heterogenous group of disorders with varying clinical presentations. The common bleeding disorders are Hemophilia A and B, von Willebrand disease, and inherited thrombocytopenias. In addition, there are a number of other defects of coagulation pathway and platelet function, about which only limited knowledge is available. This review article attempts to organize the information available regarding the clinical presentations, molecular defects and methods available for molecular diagnosis of these disorders.

Hepatitis E virus infection causing isolated fetal ascites: a case report.

Maternal hepatitis infection, excepting hepatitis E, causing isolated fetal ascites with variable outcome has been reported previously. We present a case of maternal hepatitis E virus (HEV) infection causing isolated fetal ascites which resolved spontaneously during pregnancy and resulted in a term live-born baby with anti-HEV seropositivity. A 39-year-old primigravida woman was diagnosed with acute HEV infection at 15 weeks of gestation. Ultrasound at 19 weeks showed significant fetal ascites with abdominal calcifications. Fetal karyotype did not show any abnormality. Cord blood was positive for anti-HEV IgM and negative for other intrauterine infections. Ultrasound at 25 weeks showed partial resolution of fetal ascites with complete resolution at 30 weeks. She delivered a healthy baby at 38 completed weeks, with normal liver enzymes at birth and 1-month follow-up.

Limb body wall complex.

Limb body wall complex (LBWC) is a rare clinicopathological entity, representing a compound anomaly pattern in ventral body wall defects. The authors report a case of LBWC diagnosed in early antenatal period. The pregnancy was terminated following the diagnosis. Fetal autopsy findings were typical of LBWC.