Motor neurons generate pose-targeted movements via proprioceptive sculpting

Motor neurons are the final common pathway1 through which the brain controls movement of the body, forming the basic elements from which all movement is composed. Yet how a single motor neuron contributes to control during natural movement remains unclear. Here we anatomically and functionally characterize the individual roles of the motor neurons that control head movement in the fly, Drosophila melanogaster. Counterintuitively, we find that activity in a single motor neuron rotates the head in different directions, depending on the starting posture of the head, such that the head converges towards a pose determined by the identity of the stimulated motor neuron. A feedback model predicts that this convergent behaviour results from motor neuron drive interacting with proprioceptive feedback. We identify and genetically2 suppress a single class of proprioceptive neuron3 that changes the motor neuron-induced convergence as predicted by the feedback model. These data suggest a framework for how the brain controls movements: instead of directly generating movement in a given direction by activating a fixed set of motor neurons, the brain controls movements by adding bias to a continuing proprioceptive-motor loop.

Conventional vs virtual autopsy with postmortem MRI in phenotypic characterization of stillbirths and fetal malformations

OBJECTIVE

To compare virtual autopsy using postmortem magnetic resonance imaging (MRI) with conventional autopsy with respect to phenotypic characterization of stillbirths and malformed fetuses, and acceptability to parents.

METHODS

This was a prospective diagnostic evaluation study, conducted from June 2013 to June 2015, including stillbirths and pregnancies terminated owing to fetal malformation at ≥ 20 weeks' gestation, for which parental consent to both conventional autopsy and postmortem MRI was obtained. Cases of maternal and obstetric cause of fetal demise were excluded. Whole-body postmortem MRI (at 1.5 T) was performed prior to conventional autopsy. Taking conventional autopsy as the diagnostic gold standard, postmortem MRI findings alone, or in conjunction with other minimally invasive prenatal and postmortem investigations, were assessed and compared for diagnostic accuracy.

RESULTS

Parental consent for both conventional autopsy and postmortem MRI was obtained in 52 cases of which 43 were included in the analysis. In 35 (81.4%) cases, the final diagnosis based on virtual autopsy with postmortem MRI was in agreement with that of conventional autopsy. With conventional autopsy as the reference standard, sensitivity, specificity, positive and negative predictive values of postmortem MRI were, respectively: 77.7%, 99.8%, 97.4% and 98.0% for whole-body assessment; 93.1%, 99.0%, 87.1% and 99.5% for the nervous system; 61.0%, 100.0%, 100.0% and 96.7% for the cardiovascular system; 91.1%, 100.0%, 100.0% and 98.0% for the pulmonary system; 80.6%, 99.8%, 96.7% and 98.7% for the abdomen; 96.2%, 99.7%, 96.2% and 99.7% for the renal system; and 66.7%, 100.0%, 100.0% and 97.2% for the musculoskeletal system. Virtual autopsy was acceptable to 96.8% of families as compared with conventional autopsy to 82.5%.

CONCLUSIONS

Virtual autopsy using postmortem MRI and other minimally invasive investigations can be an acceptable alternative to conventional autopsy when the latter is refused by the parents. Postmortem MRI is more acceptable to parents and can provide additional diagnostic information on brain and spinal cord malformations. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Nasopharyngeal teratoma, congenital diaphragmatic hernia and Dandy-Walker malformation - a yet uncharacterized syndrome

An association of congenital diaphragmatic hernia, dandy walker malformation and nasopharyngeal teratoma is very rare. Here, we report a fourth case with this association where chromosomal microarray and whole exome sequencing (WES) was performed to understand the underlying genetic basis. Findings of few variants especially a novel variation in HIRA provided some insights. An association of congenital diaphragmatic hernia, dandy walker malformation and nasopharyngeal teratoma is very rare. Here, we report a fourth case with this association where chromosomal microarray and whole exome sequencing (WES) was performed to understand the underlying genetic basis. Findings of few variants especially a novel variation in HIRA provided some insights.

Threshold levels of 25-hydroxyvitamin D and parathyroid hormone for impaired bone health in children with congenital ichthyosis and type IV and V skin

BACKGROUND

Patients with congenital ichthyosis, especially those with darker skin types, are at increased risk of developing vitamin D deficiency and rickets. The relationships between 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH) and bone health have not been studied previously, in ichthyosis.

OBJECTIVES

To determine the threshold levels of 25(OH)D and PTH for impaired bone health in children with congenital ichthyosis.

METHODS

In this cross-sectional study, 119 children with ichthyosis and 168 controls were recruited. Serum 25(OH)D, PTH, calcium, phosphate and alkaline phosphatase (ALP) were measured. Radiological screening for rickets was carried out only in children with ichthyosis.

RESULTS

Forty-seven children with ichthyosis had either clinical or radiological evidence of rickets. The correlation between serum 25(OH)D and PTH showed that a serum level of 25(OH)D 8 ng mL(-1) was associated with a significant increase in PTH. The correlation between PTH and ALP showed that a serum PTH level of 75 pg mL(-1) was associated with a significant increase in ALP levels. Of the different clinical phenotypes of ichthyosis, both autosomal recessive congenital ichthyosis (ARCI) and epidermolytic ichthyosis (EI) were found to have significantly increased PTH, ALP and radiological rickets scores compared with common ichthyosis.

CONCLUSIONS

Serum levels of 25(OH)D ≤ 8 ng mL(-1) and PTH ≥ 75 pg mL(-1) significantly increases the risk for development of rickets [odds ratio (OR) 2·8; 95% confidence interval (CI) 1·05-7·40; P = 0·04] in ichthyosis. Among the different types, patients with ARCI (OR 4·83; 95% CI 1·74-13·45; P < 0·01) and EI (OR 5·71; 95% CI 1·74-18·79; P < 0·01) are at an increased risk of developing rickets.

Prevalence of neonatal hypothyroidism in Kangra Valley, Himachal Pradesh

Iodine deficiency (ID) is an endemic health problem in Kangra District, Himachal Pradesh (HP). ID in pregnant mothers leads to neonatal hypothyroidism (NH), mental retardation, deaf mutism, squint, dwarfism, spastic dysplasia, neurological defects and congenital anomalies. NH can be assessed by estimating the thyroid stimulating hormone (TSH) in cord blood samples. The present study was conducted with an objective to assess the prevalence of NH in district Kangra, HP. In district Kangra, all the hospitals providing obstetric services were enlisted. Three hospitals conducting more than 100 deliveries per year were selected randomly. A total of 613 umbilical cord blood samples of neonates were collected on filter papers and analyzed for TSH. TSH was estimated by enzyme-linked immunosorbent assay method. Neonates with TSH levels ⩾20 mIU/l were recalled for reassessment of TSH for confirmation of NH. Prevalence of NH was found to be 4.4%. This finding suggests the need for the implementation of a neonatal screening program for early detection of children with ID.

Mutation spectrum in BBS genes guided by homozygosity mapping in an Indian cohort

Bardet-Biedl syndrome (BBS), a ciliopathy disorder with pleiotropic effect manifests primarily as retinal degeneration along with renal insufficiency, polydactyly and obesity. In this study, we have performed homozygosity mapping using NspI 250K affymetrix gene chip followed by mutation screening of the candidate genes located in the homozygous blocks. These regions are prioritized based on the block length and candidature of the genes in BBS and other ciliopathies. Gene alterations in known BBS (22) and other ciliopathy genes such as ALMS1 (2) were seen in 24 of 30 families (80%). Mutations in BBS3 gene, inclusive of a novel recurrent mutation (p.I91T) accounted for 18% of the identified variations. Disease associated polymorphisms p.S70N (BBS2), rs1545 and rs1547 (BBS6) were also observed. This is the first study in Indian BBS patients and homozygosity mapping has proved to be an effective tool in prioritizing the candidate genes in consanguineous pedigrees. The study reveals a different mutation profile in the ciliopathy genes in Indian population and implication of novel loci/genes in 20% of the study group.

Do alpha deletions influence hydroxyurea response in thalassemia intermedia?

Thalassemia intermedia patients show variable phenotypes. Hydroxyurea (HU) may benefit some of the thalassemia intermedia cases (1), however, the parameters influencing the response to HU have not been reported. In this study, the molecular parameters, alpha-globin and beta-globin genotype and the Xmn I polymorphism, were correlated with the HU response. Twenty patients with thalassemia intermedia were given HU (10-20 mg/kg) and responses were evaluated over a one year period. Twelve patients (60%) showed a good response to therapy with a significant increase in Hb and HbF levels and with elimination of the transfusion requirement in four patients. Four out of the twelve (33%) patients were positive for -alpha(3.7) deletions whereas none of the 8 non-responders were positive for alpha deletions. One each of the responders and non-responders were positive for alpha alpha alpha(anti-3.7) triplication. Three (25%) responsive and one non-responsive patients were homozygous for the IVS1-1 (G-->T) mutation. Three of the responsive patients with alpha deletions were also homozygous positive for Xmn I polymorphism. Thus, in addition to acting in synergy with the XmnI polymorphism, alpha deletions may be an independent factor predicting good response to HU in thalassemia intermedia, although this needs to be confirmation in larger studies.

Status of iodine deficiency in district Kangra, Himachal Pradesh after 60 years of salt iodization

BACKGROUND/OBJECTIVES

District Kangra, Himachal Pradesh(HP), India is a known endemic area for iodine deficiency disorders (IDD) since 1956. The present study was conducted in district Kangra, Himachal Pradesh with the objective to assess the prevalence of iodine deficiency in school-age children.

SUBJECTS/METHODS

A total of 1864 children in the age group of 6-12 years were included. Clinical examination of thyroid of all children was undertaken. 'On the spot' urine samples were collected from 463 children. The salt samples were collected from 327 children.

RESULTS

The total goiter prevalence of 15.8% was found. The proportion of children with urinary iodine excretion (UIE) levels <50.0, 50.0-99.9 and ≥ 100 μg/l was 2.2, 14.3 and 83.5%, respectively. The median UIE level was 200 μg/l. About 82.3% of the families were consuming salt with iodine content ≥ 15 ppm.

CONCLUSION

The population in district Kangra is possibly in a transition phase from iodine deficient (as revealed by total goiter rate of 15.8%) to iodine sufficiency (as revealed by median UIE levels of 200 μg/l).

Folic acid supplementation prevents phenytoin-induced gingival overgrowth in children

OBJECTIVE

Gingival overgrowth is an important adverse effect of phenytoin (PHT) therapy, occurring in about half of the patients. This study aimed to evaluate the effect of oral folic acid supplementation (0.5 mg/day) for the prevention of PHT-induced gingival overgrowth (PIGO) in children with epilepsy aged 6-15 years on PHT monotherapy for 6 months.

METHODS

This was a randomized, double-blind, placebo-controlled trial conducted at a tertiary level hospital from May 2008 to June 2009. Children aged 6-15 years started on PHT monotherapy within last 1 month were eligible for inclusion. Preexisting gingival overgrowth, use of other folic acid antagonists, and macrocytic anemia were exclusion criteria. Trial subjects were randomized to receive either folic acid or placebo. The primary outcome measure was incidence of any degree of gingival overgrowth after 6 months of PHT monotherapy. The trial was registered with clinicaltrials.gov (NCT00781196).

RESULTS

A total of 120 children were recruited, 62 and 58, respectively, in folic acid and placebo arms. The 2 arms were comparable at baseline. Twenty-one percent of patients in the folic acid arm developed PIGO, as compared with 88% receiving placebo (p < 0.001). Absolute risk reduction of PIGO by folic acid was 67% (95% confidence interval 54%-80%), and relative risk reduction was 0.76.

CONCLUSIONS

Oral folic acid was found to decrease the incidence of PIGO in children on PHT monotherapy, in a statistically significant and clinically relevant manner.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that folic acid supplementation, 0.5 mg/day, is associated with prevention of gingival overgrowth in children taking PHT monotherapy.

Rhizomelic chondrodysplasia punctata type 1: report of mutations in 3 children from India

Rhizomelic chondrodysplasia punctata is a rare autosomal recessive disorder characterized by stippled epiphyses and rhizomelic shortening of the long bones. We report 3 subjects of rhizomelic chondrodysplasia punctata from India and the PEX7 mutations identified in them. The common PEX7-L292X allele, whose high frequency is due to a founder effect in the northern European Caucasian population, was not identified in these patients. Instead, 2 novel alleles are described, including 64_65delGC, which was present on a single PEX7 haplotype and could represent a common allele in the Indian population.

Cystic fibrosis in India

Cystic fibrosis (CF) was considered to be non-existent in Indian subcontinent. Reports in last one decade have suggested that cystic fibrosis occurs in India but its precise magnitude is not known. Studies on migrant Indian population in United States and United Kingdom estimate frequency of CF as 1:10,000 to 1:40,000. The clinical features are similar to that reported in Caucasian population. CF in Indian children is usually diagnosed late and in advanced stage. Children are more malnourished and may have clinically evident deficiency of fat soluble vitamins. The frequency of clubbing, colonization with Pseudomonas, and laboratory evidence of pseudo-Bartter syndrome is relatively more at the time of diagnosis. Diagnostic facilities in form of sweat chloride estimation and genetic studies are not available readily. Mutation profile is different. The frequency of common mutation F508del in Indian children is between 19% and 34%. Other mutations are heterogeneous. Management of CF in India is difficult due to less number of trained manpower, limited availability, and high cost of pharmacologic agents. The determinants of early death include: severe malnutrition and colonization with Pseudomonas at the time of diagnosis, more than four episodes of lower respiratory infection per year and age of onset of symptoms before 2 months of age. To conclude, CF does occur in India; however, precise magnitude of problem is not known. There is need to create awareness amongst pediatricians, developing diagnostic facilities, and management protocols based on locally available resources.

Diagnosing and managing cystic fibrosis in the developing world

Cystic fibrosis (CF), earlier believed to be non existent in non Caucasians, is now a pan ethnic disease, having being reported from various regions of the world over last one decade. Apart from limited resources, the major problems in diagnosis and management of CF in developing countries include: lack of awareness among pediatricians, absence of facilities for diagnosis (sweat chloride estimation and genetic studies), lack of trained manpower for care of specific problems, and non availability of appropriate drugs. Care of children with CF may not be a priority for governments in countries where childhood mortality rates are high, predominantly due to acute infections. An indigenously developed and relatively inexpensive method of sweat collection and chloride estimation using pilocarpine iontophoresis and titration, respectively, may be an alternative to the commercially available costly equipment. Having a team of trained nurse, physiotherapist, and dietician for optimal care of CF patients may not be feasible due to inadequate resources. Training a single person (e.g. nurse) to deliver comprehensive CF care may be a feasible alternative. To overcome problems of non availability of appropriate drugs (enzymes, inhaled antibiotics, DNAse, etc), locally available drugs may be used. Examples include use of hypertonic saline in place of DNAse, enteric coated enzyme tablets in place of enteric coated spherules, etc. Factors that are associated with decreased survival in CF patients from developing countries are age of onset of symptoms <2 months, severe malnutrition at the time of diagnosis, colonization with Pseudomonas at the time of diagnosis and frequency of pneumonia >4 episodes/year. All these factors can be modified except onset of symptoms before 2 months of age, by early diagnosis and appropriate treatment. Many of the above mentioned hurdles have been successfully overcome by us to establish CF services in a resource-limited setting. We conclude that education of pediatricians about the disease, early diagnosis using indigenous technology and aggressive physiotherapy with nutritional management and judicious use of antibiotics can improve the quality of life and survival in CF patients in resource-limited settings.

Osteoma cutis in pseudohypoparathyroidism

Osteoma cutis is the formation of normal bone in the skin. Primary osteoma cutis occurs de novo, whereas the secondary type develops in association with the underlying inflammatory, tumorous or traumatic conditions. Primary osteoma cutis is also associated with Albright's hereditary osteodystrophy (AHO), which can include hypocalcaemic-type pseudohypoparathyroidism (also known as pseudohypoparathyroidism type Ia) or normocalcaemic-type pseudohypoparathyroidism (also known as pseudopseudohypoparathyroidism). We describe a case of osteoma cutis in a 7-year-old boy who had cutaneous, biochemical and phenotypic features of pseudohypoparathyroidism type Ia and AHO.

Mutations of human TMHS cause recessively inherited non-syndromic hearing loss

BACKGROUND

Approximately half the cases of prelingual hearing loss are caused by genetic factors. Identification of genes causing deafness is a crucial first step in understanding the normal function of these genes in the auditory system. Recently, a mutant allele of Tmhs was reported to be associated with deafness and circling behaviour in the hurry-scurry mouse. Tmhs encodes a predicted tetraspan protein of unknown function, which is expressed in inner ear hair cells. The human homologue of Tmhs is located on chromosome 6p.

OBJECTIVE

To determine the cause of deafness in four consanguineous families segregating recessive deafness linked to markers on chromosome 6p21.1-p22.3 defining a novel DFNB locus.

RESULTS

A novel locus for non-syndromic deafness DFNB67 was mapped in an interval of approximately 28.51 cM on human chromosome 6p21.1-p22.3. DNA sequence analysis of TMHS revealed a homozygous frameshift mutation (246delC) and a missense mutation (Y127C) in affected individuals of two families segregating non-syndromic deafness, one of which showed significant evidence of linkage to markers in the DFNB67 interval. The localisation of mTMHS in developing mouse inner ear hair cells was refined and found to be expressed briefly from E16.5 to P3.

CONCLUSIONS

These findings establish the importance of TMHS for normal sound transduction in humans.

Arsenic induced apoptosis in rat liver following repeated 60 days exposure

BACKGROUND

Accumulation of the wide spread environmental toxin arsenic in liver results in hepatotoxcity. Exposure to arsenite and other arsenicals has been previously shown to induce apoptosis in certain tumor cell lines at low (1-3 microM) concentration.

AIM

The present study was focused to elucidate the role of free radicals in arsenic toxicity and to investigate the nature of in vivo sodium arsenite induced cell death in liver.

METHODS

Male wistar rats were exposed to arsenite at three different doses of 0.05, 2.5 and 5mg/l for 60 days. Oxidative stress in liver was measured by estimating pro-oxidant and antioxidant activity in liver. Histopathological examination of liver was carried out by light and transmission electron microscopy. Analysis of DNA fragmentation by gel electrophoresis was used to identify apoptosis after the exposure. Terminal deoxy-nucleotidyl transferase mediated dUTP Nick end-labeling (TUNEL) assay was used to qualify and quantify apoptosis.

RESULTS

A significant increase in cytochrome-P450 and lipid peroxidation accompanied with a significant alteration in the activity of many of the antioxidants was observed, all suggestive of arsenic induced oxidative stress. Histopathological examination under light and transmission electron microscope suggested a combination of ongoing necrosis and apoptosis. DNA-TUNEL showed an increase in apoptotic cells in liver. Agarose gel electrophoresis of DNA of hepatocytes resulted in a characteristic ladder pattern.

CONCLUSION

Chronic arsenic administration induces a specific pattern of apoptosis called post-mitotic apoptosis.

An Indian child with Kindler syndrome resulting from a new homozygous nonsense mutation (C468X) in the KIND1 gene

Kindler syndrome is an inherited skin condition that presents with blistering followed by photosensitivity and a progressive poikiloderma. The disorder results from mutations in the KIND1 gene, encoding the protein kindlin-1, a recently characterized 677-amino acid protein involved in anchorage of the actin cytoskeleton to the extracellular matrix. We report the clinical features of an 11-year-old boy with Kindler syndrome from a consanguineous Indian family and the identification of a homozygous nonsense mutation (C468X) in exon 12 of the KIND1 gene in his genomic DNA. This mutation has not been described previously but is similar to the 17 previously published KIND1 mutations that are all predicted to lead to loss of kindlin-1 protein expression and function. The clinical features in this boy highlight the relevance of kindlin-1 in skin biology, specifically to epidermal adhesion and response to acute and chronic sun exposure. Delineation of this new pathogenic mutation in KIND1 is also useful for genetic counselling in this family and in assessing carrier status in unaffected family members.

Cord blood analysis for prenatal diagnosis of thalassemia major and hemophilia A

Beta thalassemia and Hemophilia A are common genetic disorders for which prenatal diagnosis (PND) is an accepted option. Our aim was to evaluate cord blood analysis as a method for PND of these disorders. Cord blood samples at 18-26 weeks gestation from nine mothers with previous thalassemia major child and five families with previous hemophilia A were studied. In the former; HbF, HbA2 and HbF were determined by high performance liquid chromatography (HPLC) and in latter; Factor VIII and IX assays were done by one stage method. In HPLC studies for thalassemia, three out of nine fetuses were affected, five were carriers and one was normal. In hemophilia PND samples, 2 out of five fetuses were affected. Thus, HPLC and factor VIII assay in cord blood are feasible alternatives for PND in Beta thalassemia and hemophilia A respectively, especially when DNA analysis is uninformative or there are financial constraints.

Novel missense mutation in the coagulation factor IX catalytic domain associated with severe haemophilia B--Factor IXDelhi

Factor IX is a vitamin K-dependent serine protease, which exists as a zymogen in the blood. On activation to factor IXa, by factor XIa or tissue factor-factor VIIa complex, it forms tenase complex with factor VIIIa, in the presence of Ca2+. This tenase complex enzymatically converts factor X to factor Xa, thereby bringing about the coagulation cascade. Mutations in factor IX gene have been shown to cause haemophilia B, which is inherited as an X-linked recessive disorder. Herein we report a novel missense mutation at the nucleotide position 30829-T > A in the exon 8 of factor IX gene. This transversion leads to the substitution of histidine 236 to glutamine. This resulting abnormal protein has been named factor IXDelhi. Molecular modelling was performed to predict the molecular pathology of this mutation. We predict that this change in the catalytic domain may affect the surface loop that accommodates Ca2+, thereby leading to severe bleeding disorder.

Can throat swab after physiotherapy replace sputum for identification of microbial pathogens in children with cystic fibrosis?

OBJECTIVE

To compare cultures throat swab after physiotherapy with results of sputum culture in identification of lower airway pathogens in children with cystic fibrosis.

METHODS

387 samples of sputum cough swabs, throat swab and throat swab after physiotherapy were collected from 48 patients of cystic fibrosis and cultured for aerobic bacteria. The results of cultures of cough swabs, throat swab and throat swab after physiotherapy were compared with results of sputum culture.

RESULTS

There was good concordance between culture results of sputum and other methods. Over all concordance was 70%, 81% and 92% with cough swab, throat swab and throat swab after physiotherapy. Sensitivity for isolation of Pseudomonas aeruginosa by throat swab, cough swab and throat swab after physiotherapy was 40%, 42% and 82% respectively. Specificity for isolation of Pseudomonas by throat swab, cough swab and throat swab after physiotherapy was 99%, 100% and 99% respectively. Sensitivity for isolation of Staphylococcus aureus by throat swab, cough swab and throat swab after physiotherapy was 57%, 50% and 100% respectively. Specificity for isolation of Staphylococcus by throat swab, cough swab and throat swab after physiotherapy was 99% for all these methods.

CONCLUSION

It is concluded that throat swab after physiotherapy in a child with CF can be used reliably for identification of lower airway pathogens.

A case of dextrocardia, radial ray malformation and renal anomaly

A 12-year-old boy is described with bilateral radial club hands, scoliosis, hypospadias, isolated dextrocardia, hypoplastic ribs, an ectopic kidney and spina bifida occulta. Although some of the clinical features of this patient are seen in VATER association and sacrococcygeal dysgenesis, the presence of dextrocardia, facial dysmorphism, radial, renal and vertebral anomalies preclude these diagnoses.

Prenatal diagnosis in hemophilia A using factor VIII gene polymorphism--Indian experience

The heterogeneous nature of the mutations, the size, and the complexity of the factor VIII gene makes direct mutation analysis in hemophilia A families in India an option that is not very feasible and practical. Thus, carrier screening and prenatal diagnosis of hemophilia A often depends on haplotype analysis using restriction fragment length polymorphisms (RFLP) and short tandem repeat (STR) markers to track the defective factor VIII gene within a family. The main objective of this present study was to assess the utility of using polymerase chain reaction (PCR)-based five polymorphic markers: four intragenic Hind III, Bcl I, intron 13, and intron 22 STRs and one extragenic marker St14 in prenatal diagnosis. Forty-one chorionic villus samples (CVS) were studied from 41 families with a history of hemophilia A. PCR and RFLP were used for screening. Intron 22 STR showed the highest informativeness (60.9%), followed by Hind III (51.2%), Bcl I (46.3%), & intron 13 STR (51.2%); the extragenic marker St14 (VNTR) was informative in 46.3% of families. Linkage analysis, with the combined use of these five PCR-based polymorphic markers, gives good informativeness of 87.8% in the Indian population. Of the 41 CVS tested, 21 were found to be male fetuses and of these 13 were found likely to be affected with hemophilia A. Only in 12.2% of the families were none of the markers informative.

Origins and frequencies of SLC26A4 (PDS) mutations in east and south Asians: global implications for the epidemiology of deafness

Recessive mutations of SLC26A4 (PDS) are a common cause of Pendred syndrome and non-syndromic deafness in western populations. Although south and east Asia contain nearly one half of the global population, the origins and frequencies of SLC26A4 mutations in these regions are unknown. We PCR amplified and sequenced seven exons of SLC26A4 to detect selected mutations in 274 deaf probands from Korea, China, and Mongolia. A total of nine different mutations of SLC26A4 were detected among 15 (5.5%) of the 274 probands. Five mutations were novel and the other four had seldom, if ever, been identified outside east Asia. To identify mutations in south Asians, 212 Pakistani and 106 Indian families with three or more affected offspring of consanguineous matings were analysed for cosegregation of recessive deafness with short tandem repeat markers linked to SLC26A4. All 21 SLC26A4 exons were PCR amplified and sequenced in families segregating SLC26A4 linked deafness. Eleven mutant alleles of SLC26A4 were identified among 17 (5.4%) of the 318 families, and all 11 alleles were novel. SLC26A4 linked haplotypes on chromosomes with recurrent mutations were consistent with founder effects. Our observation of a diverse allelic series unique to each ethnic group indicates that mutational events at SLC26A4 are common and account for approximately 5% of recessive deafness in south Asians and other populations.

An indigenously developed method for sweat collection and estimation of chloride for diagnosis of cystic fibrosis

An indigenously developed method for sweat collection and titration method for estimation of chloride was validated. The mean difference in estimated chloride value from the known strength of saline in 50 samples was -1.04 +/- 4.13 mEq/L (95% CI: -0.07 to 2.28). The mean difference in the estimated chloride values between two observers when the test was performed on known strengths of saline solution was -2.5 +/- 4.24 mEq/L (95% CI: -3.67 to 1.33). The inter observer variability between two observers when the test was performed on sweat samples obtained from 50 individuals was -1.12 +/- 4.34 mEq/L (95% CI: -2.23 to 0.8 ). Sweat weight of more than 100 mg could be collected in first attempt in 602 of 757 (80%) patient with an average sweat weight of 230 mg. This inexpensive method of sweat collection and chloride estimation has acceptable accuracy and repeatability and can be used in resource poor setting for making a diagnosis of cystic fibrosis.

Factor IX gene polymorphisms in Indian population

Hemophilia B is an X-linked, recessive disorder of hemostasis, caused by a defect in coagulation factor IX. To date, several restriction fragment length polymorphisms (RFLPs) have been identified within the gene for human factor IX. The incidence of these RFLPs differs significantly in different populations. In the present study, we analyzed the heterozygosity frequency and the allele frequency of three common intra- and extragenic polymorphic sites of the factor IX gene in Indian population. The main objective was to test the informativeness of two intragenic markers Dde I and Xmn I and one extragenic marker Hha I for carrier detection and prenatal diagnosis. The method used was polymerase chain reaction (PCR) and RFLP, which is economical yet simple to perform. In Indian population Dde I marker showed an informativeness of 69.0% followed by 38.0% for Hha I and 23.0% for Xmn I. The cumulative informativeness of these three markers was found to be 80 to 82%. A comparison of the heterozygosity rates of these three markers with the other ethnic groups showed that Indian population had almost similar pattern with the Caucasians and American blacks but differed significantly from the Orientals including Japanese, Chinese and Malays.

Congenital adrenal hyperplasia presenting as hematuria and acute renal faliure

We present a neonate who presented with hematuria and acute renal failure. Classical 21 hydroxylase deficiency was diagnosed on the basis of features of salt wasting, response to treatment with corticosteroids and mineralocorticoids and a positive ACTH stimulation test. Renal vein thrombosis secondary to hemoconcentration due to salt wasting was attributed as the cause of hematuria. Follow-up revealed clinical improvement and normalization of renal parameters. This is the first report of congenital adrenal hyperplasia presenting as hematuria and renal failure to the best of our knowledge.

Prenatal diagnosis of haemoglobinopathies

BACKGROUND

Haemoglobinopathies constitute a major health problem in the Indian subcontinent. In the absence of any method for achieving complete cure and treatment being expensive, prenatal diagnosis and selective termination of an affected foetus is a feasible option to decrease the disease load. We report our experience with prenatal diagnosis of haemoglobinopathies over a two-and-a-half year period in 257 pregnancies.

METHODS

Amplification refractory mutation system (ARMS) was used to detect beta-thalassaemia, haemoglobin E and sickle cell mutations.

RESULTS

Five mutations in the beta-globin gene which are common in the Indian population were detected in 92.3% of mutant chromosomes, whereas 3.1% of chromosomes carried rare mutations followed by 0.8% haemoglobin E and 0.4% sickle cell mutations. Mutations in 3.3% chromosomes were uncharacterized. The prenatal procedure, carried out early in pregnancy, was a chorionic villus sampling in most cases. A confirmed diagnosis based on ARMS-PCR was given in 241 (93.8%) cases. In 10 cases (3.9%) linkage analysis was required to confirm the foetal status, as mutations in both parents were not identified or the chorionic villus sample carried the single identified mutation. Four families with haemoglobin E-beta thalassaemia and one family with sickle cell disease were also included. Of the study population, 91.25% of the couples had a previous child with haemoglobinopathy, whereas 8.75% of the couples came before the birth of the first affected child.

CONCLUSION

We conclude that ARMS-PCR is a highly sensitive technique for detecting mutations in the beta-globin gene and its efficacy in the prenatal diagnosis of haemoglobinopathies is proven.

Spectrum of floppy children in Indian scenario

OBJECTIVE

To study the clinical profile of paralytic floppy infants undertaking available investigations and detect the frequency of exon7 of survival motor neuron (SMNT) gene deletion among the spinal muscular atrophy (SMA) cases.

DESIGN

Descriptive study.

SETTING

Tertiary care teaching hospital.

SUBJECTS

70 paralytic floppy infants (40 males/30 females) with age less than 13 years were included in the study. Exclusion criteria included central hypotonia of any cause. Detailed clinical evaluation was done followed by serum creatine phosphokinase levels, electrophysiological studies, muscle biopsy including immunohistochemistry and electron microscopy. Exon7 of SMNT gene deletion studies was done by PCR.

RESULTS

Final diagnosis of SMA was assigned to 37 patients followed by congenital myopathy (n = 7), cogenital muscular dystrophy (n = 5), mitochondrial myopathy (n = 4), neuropathies (n = 5) and diaphragmatic SMA (n = 1). Only 15.7% of cases remained unclassified. When EMG was correlated with final diagnosis, it was 80.6% and 75% sensitive and 68.8% and 87.5% specific for neurogenic and muscle disease, respectively. Muscle biopsy revealed neurogenic atrophy in 47.8% cases followed by normal in 37.3% and myopathic pattern in 14.97% cases. Exon7 of SMNT gene was deleted in only 50% of SMA cases.

CONCLUSIONS

Spinal muscular atrophy was the commonest cause of floppy children. The low rate of SMNT gene deletion detected needs confirmation with further studies.

Adhalin deficiency: an unusual cause of muscular dystrophy

Childhood muscular dystrophies have a wide clinical spectrum, motor disability and are variably inherited. Although the phenotype may appear similar they may represent distinct genetic entities. Advances in immunohistochemistry, gene deletion and linkage studies have enabled precise characterization. We report a family with an early onset weakness and calf pseudo hypertrophy in 2 male sibs with an usually mild course. Deletion screening was negative for 24 exons of the DMD gene in both. Muscle immunohistochemistry revealed normal dystrophin I and II staining but complete absence for adhalin, a dystrophin associated glycoprotein. Classifying them as adhalinopathy. Severe childhood autosomal recessive muscular dystrophies (SCARMD) result from mutation in the sarcoglycan complex (59). Adhalinopathy is now used to describe SCARMD. The adhalinopathy described in our patients is the first report from India.