The multi-racial, multi-lingual, multi-religious, and multi-cultural Malaysia is situated at the crossroads of Southeast Asia. It has a total population of about 23 million, comprising of more than fifty ethnic groups: Malays, Chinese, Indian, and the minorities of Orang Asli in Peninsular; Iban, Bidayuh, Melanau, Kenyah Kayan, Ukit, Penan, Sekapan, Lahanan, Lun Bawang, Kelabit, Berawan, Punan Bah etc. in Sarawak; and Kadazan, Bajau, Murut, Paitan, Suluk Bonggi, Illanun, Bengkahak Tidung etc. in Sabah. The origin of the multi-ethnic character of this country traces back to decades of human migration from various regions of Southeast Asia. With her rich human biodiversity, a study of the human population genetics is imperative, either for forensic database purposes, or as the stepping stone for medical applications.
Generally, the karyotype profile of Down Syndrome has been reported to be full trisomy 21 in 92% of patients, mosaic trisomy 21 in 4% of patients and translocation involving chromosome 21 in 4% of patients in most of the population groups worldwide. But, karyotype analysis of 149 DS patients at the Human Genome Center, USM, during the past five years revealed that free trisomy accounted for 94.6%, mosaic trisomy 21 for 4.7% and translocation involving chromosome 21 in 0.7% of the Down Syndrome etiology in North East Malaysian population, indicating a low frequency of translocation DS in this region. Here, we report one case of translocation Down Syndrome encountered during karyotype analysis of 149 DS cases. Karyotype showed a robertsonian translocation where an entire extra chromosome 21 was attached to the centromere of one of the chromosome 14, resulting in a derivative chromosome 14 with attached chromosome 21. Karyotype analysis of the parents revealed a normal 46,XY pattern for father and 46,XX pattern for mother indicating that this robertsonian translocation had arisen de novo either prior to or at conception.
Spinal Muscular Atrophy (SMA) is a heredity neuromuscular disorder and is one of the most common genetic causes of childhood fatality. SMA is classified into three groups based on age of onset and achieved motor milestone. Survival Motor Neuron (SMN) gene has been identified as the responsible gene for SMA. From August 2003 until Feb 2007 we have received 93 samples for SMN1 gene deletion analysis from various hospitals in Malaysia. All the patients except for 3 patients were Malaysian (71 Malays, 5 Indians, 9 Chinese and 5 patients are mixed ethnicity). DNA were extracted from blood samples using DNA extraction kit and subjected to SMN/ gene deletion analysis by PCR-RE. Forty nine out of 93 samples (20 type I, 21 type II, and 8 type III) were found to have homozygous deletion of at least exon 7 of the SMN1 gene. Twelve patients (7 type I, 4 type II, 1 type III) showed the presence of the SMN1 gene and the rest were excluded as they did not fulfill the criteria of International SMA Consortium. Deletion analysis of exon 7 of the SMN gene can be an alternative to the existing diagnostic modalities of SMA.
Introduction: Isolation of specific cell types is important in providing a better understanding of hematological disorders. The knowledge of molecular biology aspect in β-thalassemia is still limited. This is because hemoglobin disorder involves various erythropoietic processes in which the genetic information is lack due to enucleation of red blood cells occurs in bone marrow. It is invasive to collect samples from bone marrow and cord blood although nucleated red blood cells (NRBCs) are abundant in these sites. NRBCs are precursors of red blood cells and typically found in peripheral blood (PB) of β-thalassemia major patients and abundant post-splenectomy. The utilization of PB NRBCs will provide a further understanding of the molecular aspects of ineffective erythropoiesis in β-thalassemia major patients. Objective: The objective of this study was to isolate the NRBCs using CD71 magnetic beads from PB of β-thalassemia major; non-splenectomy and post-splenectomy patients. Methods: NRBCs were isolated from 6 mL PB of β-thalassemia major patients based on density gradient and magnetic activated cell sorting (MACS) for NRBCs enrichment using a CD71 marker. Cell count was determined by using hemocytometer (Weber Scientific, NJ, USA) and BD FACSCantoTM II flow cytometry (Becton-Dickson, NJ, USA) was performed for method validation. Results: NRBCs were successfully isolated from the PB of both non-splenectomy and post-splenectomy β-thalassemia major patients with >90% specificity by flow cytometric analysis. The median number of enriched NRBCs (x104 ) was 58.5 (283) and 340 (338) respectively using hemocytometer. Conclusion: The MACS method was found to be convenient and efficient in the isolation of the targeted cells for downstream applications.