Comparison of serum creatine kinase estimation with short tandem repeats based linkage analysis in carriers and affected children of Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy [DMD] is an X-linked recessive lethal, genetic disorder characterised by progressive weakness of skeletal muscles which is untreatable and transmitted to males by carrier females. Advances in laboratory techniques now focus direct mutational analysis as the most reliable and indirect analysis based on Short Tandem Repeats [STR] based linkage analysis as feasible, inexpensive, and efficient method for carrier detection and prenatal diagnosis. The objective of this study was to compare the sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and diagnostic efficiency of Serum Creatine Kinase [SCK] with Short Tandem Repeats [STR] based linkage analysis in carriers and affected children of Duchenne Muscular Dystrophy. The study was carried out from Dec 2006 to Dec 2007 in families having index clinical cases of DMD who were referred from different hospitals for evaluation/workup of DMD. SCK was done as a preliminary investigation in all index cases. The PCR assay with STR based linkage analysis with Intron 44, 45, 49 and 50 of DMD gene were performed in all families. Six families were informative with Intron 44 of DMD gene and one family was non-informative with all four intronic markers of DMD. SCK analyses were done in all the family members and compared with PCR analysis in informative families. SCK was not performed on Chorionic villous sample [CVS] done for prenatal diagnosis of DMD, and CVS and non-informative family members were excluded from the study. In carriers of DMD, the sensitivity and negative predictive value of SCK were 33.3%, and specificity and positive predictive were 100% with diagnostic efficiency of 50%. In affected cases of DMD the sensitivity and negative predictive value of SCK were 100%, and specificity and positive predictive were 91% and 88.8% respectively and diagnostic efficiency of 94.1%. The SCK is an excellent screening test for affected cases of DMD. For carrier identification we have to resort on PCR analysis so as to provide safer diagnostic tool for genetic counselling and prenatal diagnosis

Feasibility of short tandem repeats [STR] analysis for carrier detection and prenatal diagnosis in families with duchenne muscular dystrophy [DMD]

To determine the feasibility of Short tandem Repeats [STR] based linkage analysis for carrier detection and prenatal diagnosis [PND] in families having children affected with Duchemnne Muscular Dystrophy. Case series. Department of Chemical Pathology and Endocrinology in collaboration with Department of Molecular Biology, Armed Forces institute of Pathology [AFIP], Rawalpindi. From February 2007 to January 2008. six unrelated families with at least one affected child in each family who had characteristic features of DMD [index case]. PCR for Duchenne Muscular Dystrophy was carried out with STR based linkage analysis at introns 44, 46, 49 and 50 of DMD gene. Thermal cycling in TC-480 [Perkin Elmer] included 25 cycles each comprising 30 sec denaturation at 94 [degree sign] C, annealing at 62 [degree sign] C for 30 sec, extension at 65 [degree sign] C for 2 min. The final extension was done for 3 min. The amplified products were run on 8% nondenaturing polyacrylamide gel electrophoresis [PAGE] carried out at 200V for three hours on electrophoresis apparatus [Bio-Rad UK]. The gels were stained in silver nitrate. By comparing STR pattern of X-chromosome allele of index case with X-chromosome alleles of the mother, the diseased or affected X-chromosome was ascertained. Carrier detection and prenatal diagnosis was feasible with STR marker at intron 44 in DMD families. It was informative in 5 out of 6 DMD families. Carrier detection and PND by STR based linkage analysis is technically feasible in Pakistani families with DMD

Evaluation of post challenge Glucose Estimation For Diagnosis of Gestational Diabetes Mellitus [W.H.O. - Criteria 1999]

To compare sensitivity, specificity and Positive Predictive Value [PPV] and Negative Predictive Value [NPV] of 75g Oral Glucose Tolerance Test [OGTT] i.e. WHO criteria 1999 with 100g OGTT of National Diabetes Data Group [NDDG criteria]. Study Design: Comparative cross sectional. Material and Methods:The study was conducted at Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology [AFIP], Rawalpindi. Duration of study: 1st January 2004 to 31st August 2004. Sample size: Approx one hundred pregnant ladies between 24 to 28 gestational weeks. Sampling technique: Non-probability convenience. Data collection procedure: Patients consent for participation in the study was taken with explanation of test procedure. Patient's characteristics such as age, obesity, family history of diabetes, pregnancy induced hypertension, previous bad obstetric history [of still birth, macrosomia, recurrence abortion] was recorded on a predesigned proforma. Patients were first called for 75g OGTT and then after a gap of 1-2 days for OGTT 100g. Both tests were performed according to standard protocols. OGTT 75g was found to have 87.5% sensitivity, 97.8% specificity, and 77.7% positive predictive value and 98.8% negative predictive value, when compared with 100g OGTT