Carrier detection in Duchenne muscular dystrophy using molecular methods.

Background & objectives: Duchenne and Becker muscular dystrophies are X-linked allelic disorders which are caused by mutations in the DMD gene. Carrier analysis in DMD is complicated due to the heterozygous nature of the X chromosome. Several techniques have been tried for carrier analysis in families where the mutation is identified including quantitative multiplex PCR (qmPCR), Southern blot, and now multiplex ligation-dependent probe amplification (MLPA). Linkage analysis is used in cases without identifiable mutations. The present study was undertaken to determine the status of probable carriers in families where the DMD deletion/duplication has been identified for the affected index cases. Methods: Carrier status was present in 150 probable carriers from 110 apparently unrelated families where the patients’ mutations were known. Of these 110 families, 100 were deletions, 9 duplications and 1 point mutation. Multiplex ligation-dependent probe amplification (MLPA) was used to assess the copy number changes and direct sequencing was used for the case with the point mutation. Results: Of the 150 cases, 49 were found to be carriers. Among the sporadic cases, it was observed that the rate of de novo mutations was very high (71%) as compared to the hereditary cases (29%), which was higher than the calculated rate (30%). It was observed that this difference was more apparent in deletion mutations than in duplications. Interpretation & conclusions: Identifying the DMD carrier rates in the families with unidentified deletions and duplications and where the causative mutation could be small insertions/deletions or point mutations could throw more light into this observation. MLPA was found to be useful in detecting copy number changes in DMD carriers and this could be the method of choice for DMD carrier analysis, when the mutation is detected in the affected child.

Dengue fever epidemic in Chennai--a study of clinical profile and outcome.

Children with dengue fever presenting to the Institute of Social Pediatrics, Government Stanley Hospital, during the months of October to December 2001, were prospectively followed up for clinical profile and outcome. Commonest clinical features were fever, vomiting, bleeding, body pain and hepatomegaly. Elevated liver enzymes and low platelet counts were common laboratory findings in dengue. Hepatomegaly, positive tourniquet test, elevated haematocrit and thrombocytopenia were more common in DHF and DSS group. Retro-orbital pain was slightly more in DHF and DSS groups and there was a tendency for DSS to present at an earlier age. There was no correlation between platelet counts and bleeding in classical dengue cases.

Comparison of phenobarbitone, phenytoin with sodium valproate: randomized, double-blind study.

OBJECTIVE: To compare the efficacy and side effects of phenobarbitone (PB), phenytoin (PHT) and sodium valproate (SVP) in controlling generalized tonic-clonic convulsions (GTC). DESIGN: Randomized, double blind clinical trial. SETTING: Out-Patients in a tertiary care hospital. PATIENTS: 151 children with GTC, aged 4-12 yrs, from Madras city were enrolled. At the end of 2 yrs, 127 children remained in the study. INTERVENTION: Each child was given one active drug and 2 placebo tablets. Clinical, hematological and biochemical evaluations were done every month. Serum drug levels were assessed periodically. MAIN OUTCOME MEASURES: Recurrence of convulsion and side effects. RESULTS: The proportion of children with recurrence did not differ among the 3 groups. More than one side effect was observed in 16 (32%) children on PB, 20 (40%) children on PHT and 9 (19%) children on SVP and this difference was statistically significant (p < 0.05). Hyperactivity was the major side effect of PB, observed in 22% of children. CONCLUSION: All 3 drugs were equally effective in controlling seizures. Side effects were minimal with SVP followed by PB. Though side effects were more frequent with PHT, most of them disappeared on adjusting drug dosage. Least expensive phenobarbitone may be preferred as the first drug of choice but, only for pre-school children. SVP is advised for school going children.

Isolation of Mycobacterium tuberculosis from cerebrospinal fluid by the centrifugation & filtration methods.

Cerebrospinal fluid (CSF) samples were collected in 2 bottles each, from 112 children, examined clinically for tuberculous meningitis (TBM) One was processed by the centrifugation method and the other by the filtration method for the isolation of M. tuberculosis. Of these specimens, 11 and 13 yielded M. tuberculosis by the centrifugation method and the filtration method, respectively. In 7 specimens M. tuberculosis was isolated by both the methods; in 4, only by the centrifugation method, and in 6, only by the filtration method. Using both the methods, 17 (15.2%) of 112 specimens were culture positive for M. tuberculosis. The improvement in the rate of isolation, thus obtained, assumes importance as the confirmation of the diagnosis of TBM in all the clinically suspected cases is always desired. Moreover, the filtration method is simple and inexpensive and it can be carried out even in remote hospitals and the membranes, after filtration, can be transported to central mycobacteriology laboratory for culture of tubercle bacilli.

Tuberculous meningitis in children--clinical profile, mortality and morbidity of bacteriologically confirmed cases.

One hundred and seven cases of tuberculous meningitis were registered as a part of a case-control study during the period 1990-1992. The CSF of all cases was positive for culture and/or smear for acid fast bacilli. Children were examined at the time of admission and at the time of discharge and they were contacted at the end of 1 year. Clinical picture, mortality and morbidity were analyzed. Mortality of children during the first month of illness was 22%. Some of the cases presented as acute neurological illness. We also came across CSF picture with minimal cytological and biochemical changes but with positive culture results.

Testing compliance of drug taking--a simple bed side method.

Assessment of compliance in drug taking is a problem in a crowded Outpatient Department. Using riboflavin as a urinary marker is a simple and rational method. Identifying riboflavin in the urine by fluorescence on exposure to ultraviolet (UV) rays or torch light is being used in medical practice but not extensively. In this study, the validity and reliability of these methods were assessed. The sensitivity and specificity of this test by UV method was 86% and 82% for Reader I (medical person) and 82% and 94% for Reader II (paramedical person). For Reader I, the accuracy of reading by UV lamp was the same as torch light (85%) whereas for Reader II the accuracy was better with UV lamp (87%) than with torch (79%). In reading the fluorescence by UV lamp the crude agreement between the 2 readers was 82% and chance corrected agreement was 64%. UV lamp method appears to be a reliable way of assessing compliance both by medical and paramedical persons whereas torch method appears to be more reliable when used by a medical person than by a paramedical person.

Migraine in children.

A descriptive study was carried out to find out the clinical profile, and electroencephalographic (EEG) changes in children with migraine. Screening for urinary excretion of 5-hydroxy indole acetic acid (5-HIAA) was carried out. Fifty children suffering from migraine as per Prensky's criteria were recruited over a period of 1 year. Forty six children were suffering from common migraine and 4 had classic migraine. The most common precipitating factors were physical strain and psychological stress like examination fear, fear of teacher and fights with friends. Abnormal EEG recordings were seen in 35 out of 50 patients. Urine samples taken during the headache free period were negative for 5 HIAA. Among the samples taken during the episode of headache, only 1 was positive for 5-HIAA. It is concluded that common migraine is more prevalent than classic migraine. Clinical criteria is the only way of diagnosing migraine. Since EEG changes are non-specific, this cannot be used as a diagnostic test. Biochemical analysis is expensive and less sensitive.

Role of phenobarbitone in preventing recurrence of febrile convulsions.

A randomized double blind placebo controlled trial was carried out to study the effect of phenobarbitone (PB) in preventing recurrences of simple and atypical febrile convulsions among children in the age group 6 months to 6 years. Children with simple febrile convulsions were randomly allocated to receive either phenobarbitone or placebo. Children with atypical convulsions were treated with phenobarbitone, as a third group. Thirty children were admitted in each group. All the children were followed up for a period of twelve months. Recurrence of convulsions and side effects of PB were recorded. Recurrence occurred in only 7% (95% confidence interval: 1-22) of children on Phenobarbitone, suffering from either simple or atypical febrile convulsions, compared to 53% (95% confidence interval: 34-72) of children on placebo, suffering from simple febrile convulsions. With Phenobarbitone, 5% of children had intolerable side effects. These results suggest that long term prophylaxis with phenobarbitone, even in simple febrile convulsions will be useful.

Risk factors for recurrence of febrile convulsions.

A cohort of hundred children with febrile convulsions, in the age group of 3 months to 5 years were followed up prospectively for one year to study the natural course of the illness, and to determine if specific factors would increase the risk of recurrence of febrile convulsions. The risk factors studied were age of onset under one year, long duration of convulsion (more than 15 minutes), family history of febrile convulsion or epilepsy and combination of two or all of the above factors. Four groups of children with different risk factors were followed up for recurrence of convulsion, after the first attack. A group of children without any risk factor was considered as control and they were also followed up for recurrence of convulsions. Though all the groups with the risk factors, showed a trend towards a higher recurrence rate when compared to controls, the difference observed clinically was not significant statistically. This could be due to the small sample size of each group. A larger study could throw light on the predictive value of these risk factors and narrow down the use of long term anticonvulsant prophylaxis.

Influence of maternal nutritional status on mode of delivery and asphyxia neonatorum.

To assess the influence of maternal malnutrition on the mode of delivery and asphyxia neonatorum, a cross sectional survey of 615 women in the age group of 20-28 yrs at the time of delivery was done. Women with chronic ailments and complicated pregnancies were excluded. The mothers were then classified into three groups based on Weight Height Product Index (WHPI) namely well nourished (WN), moderately malnourished (MMN) and severely malnourished (SMN). The proportion of asphyxiated babies among the three groups did not differ (P greater than 0.05). Abnormal deliveries like caesarean section were more common among SMN group compared to WN group ((P less than 0.01). No such difference was made out between MMN and WN groups (P greater than 0.05).