ABSTRACT
Background and Objective: Alpha [alpha] thalassemia is a hereditary disorder and is caused by deletions or mutations in globin genes. It is present in two clinically significant forms: hemoglobin Bart hydrops fetalis [Hb Bart] syndrome and hemoglobin H [HbH] disease. It is highly prevalent in South-East Asia or Mediterranean countries. The most common deletion reported in alpha thalassemia in Pakistani population was -alpha[3.7] with a frequency of 8.3%, and the rare forms were -alpha[4.2] [0.2%] and alphaalphaalpha[anti3.7] [0.9%]. In our study, diagnosis of severe anemia cases without any alpha and beta mutations or deletions were made by using extended alpha thalassemia deletions panel. The main objective of this study was to determine the prevalence and to study the spectra of alpha thalassemia gene deletions in beta thalassemia patients with the use of an extended panel including -[SEA], --[FIL], --[MED], --[20.5], --[THAI] in addition to -alpha [3.7], -alpha [4.2] and - alphaalphaalpha[anti3.7]
Methods: The samples were collected in ethylenediaminetetraacetic acid [EDTA] vacutainers. A total of 156 samples were analyzed for alpha thalassemia mutations. This cohort included 121 samples of beta thalassemia major, nine samples of beta thalassemia minor and 26 without any evidence of beta thalassemia mutations. DNA was extracted with Qiagen extraction kit. The primers for determination of different subsets of alpha thalassemia deletions were included. PCR amplification was performed and result interpreted on agarose gel
Results: Co-inheritance of alpha thalassemia [-alpha [3.7], -alpha [4.2]] with homozygous beta thalassemia was detected in 30% cases of studied cohort [37 out of 121]. The most common found was -alpha[3.7] deletion [35/37] as single/double deletions or in combination with -alphaalphaalpha[anti3.7]. In undiagnosed cases screened for beta thalassemia major, we found Mediterranean [-alpha [MED]] deletion at specifically 875 bp on agarose gel. This is distinctive finding in case of detecting -alpha [MED] instead of any other deletion from Pakistan
Conclusion: Alpha thalassemia deletions [-alpha[3.7], -alpha[4.2]] are the common co-inherited deletions found in beta thalassemia major patients. On the basis of results, we propose an extended alpha thalassemia genetic mutation panel should be used for screening of children presenting with anemia with suspicion of haemoglobinopathy
ABSTRACT
The immunochromatographic rapid tests facilitate the early diagnosis of dengue by providing evidence of the presence of virus specific proteins [antigens/ antibody] in human blood. Many products for rapid dengue diagnosis are available in the market; the performance of few selected products was evaluated and compared with enzyme linked immuno sorbent assays [ELISA]. Sera from a large number of patients [n=184] admitted to National Institute of Blood Diseases and Bone Marrow Transplantation [NIBD] were used to determine the efficiency of non-structural [NS] 1, IgA, IgG and IgM based rapid test devices for dengue diagnosis. The dengue NS1 antigen based device was least efficient while among the antibody based devices the dengue IgA rapid test [RDT] was comparatively better [specificity: 80.95%; sensitivity: 85.21%]. This device could detect both primary and secondary dengue infection and was found to be the most sensitive device at all point of sample collection. The dengue IgA RDT could be a cost effective and efficient rapid test device for timely dengue diagnosis at all levels of healthcare settings