Clinical and Haematological Parameters of Commonly Reported Non-deletional α-thalassaemia Mutations in Southeast Asia: A Review

@#Alpha (α)-thalassaemia is a common genetic disorder worldwide caused by the deletion and rarely non-deletional mutations of the α-globin gene. Nearly 70 types of non-deletional mutations have been reported worldwide, and this review focuses on the common ones affecting α-thalassaemia patients. The common mutations are initiation codon mutation, codon 30, haemoglobin (Hb) Constant Spring, Hb Quang Sze, Hb Adana and Hb Evora. The haematological parameters of non-deletional mutations usually show mild changes. However, a severe reduction in haemoglobin level, mean corpuscular haemoglobin (MCH), mean corpuscular volume (MCV), and mean corpuscular haemoglobin count (MCHC) has been observed among compound heterozygous HbH disease, involving both deletional and non-deletional mutations. Although non-deletional mutations are rarely reported, it requires the study of more cases to understand the clinical phenotypes that lead to severe clinical manifestations.

Acute Abdomen: Unmasked the Bleeding Site in Severe Haemophilia A

@#Haemophilia A is an inherited bleeding disorder, commonly involve soft tissues and joints. Gastrointestinal tract bleeding, are not uncommon but seldom highlighted. A 23-year-old male with underlying severe haemophilia A was presented with a generalised abdominal pain for 2 days, abdominal distension, diarrhoea and vomiting. He did not have any trauma to the abdomen. Abdominal examination revealed generalized tenderness with sign of guarding on palpation. Laboratory investigations revealed isolated, prolonged activated partial thromboplastin time (APTT) with normal total white blood cell count and haemoglobin level. In view of acute abdomen, which was not resolved by conservative treatment, an emergency laparotomy was done with FVIII concentrate and recombinant factor VII (rFVII) coverage. Intraoperative findings noted patchy gangrenous spots of about 30 cm in length in the small bowel. Histopathology examination revealed an evidence of haemorrhage within the submucosal and intramuscularis layer from the resected specimen. This case highlighted the possibility of gastrointestinal bleeding without prior trauma, which can be presented as acute abdomen in severe haemophilia patient.

Familial antithrombin III deficiency in a Malay patient with massive thrombosis

Patients with low antithrombin III (AT III) has increased risk for arteriovenous thromboembolic (TE) disease. We report a 28-year-old Malay lady who presented with spontaneous right calf pain and swelling of one week duration. She was on oral contraceptive pills and had a history of travelling for a long distance prior to the presentation. Her brother who was diagnosed with AT III deficiency had arterial thrombosis at a young age. She was diagnosed as having right popliteal vein thrombosis by ultrasound and treated with subcutaneous fondaparinux. While on treatment, she developed massive bilateral pulmonary embolism (PE). Thrombophilia study showed reduced AT III activity (38μl/dl) and normal results for protein C, protein S, activated protein C resistance and lupus anticoagulant assays. This patient has heterozygous AT III deficiency added with significant acquired factors responsible for the TE events. Those with AT III deficiency may have resistance to heparin therapy and require higher doses of heparin.

Detection of β-globin Gene Mutations Among β-thalassaemia Carriers and Patients in Malaysia: Application of Multiplex Amplification Refractory Mutation System– Polymerase Chain Reaction

Background: β-thalassaemia is one of the most common single-gene disorders worldwide. Each ethnic population has its own common mutations, accounting for the majority of cases, with a small number of mutations for the rarer alleles. Due to the heterogeneity of β-thalassaemia and the multi-ethnicity of Malaysians, molecular diagnostics may be expensive and time consuming. Methods: A simple polymerase chain reaction (PCR) approach involving a multiplex amplification refractory mutation system (MARMS) and one amplification refractory mutation system (ARMS), consisting of 20 β-globin gene mutations, were designed and employed to investigate β-thalassaemia patients and carriers. Results: Out of 169 carriers tested with the MARMS, Cd 41/42 (–TTCT), Cd 26 (A–G) HbE, IVS 1–1 (G–T), and IVS 1–5 (G–C) were the most common mutations, accounting for 78.1%. Among the Malays, Cd 26 (A–G) HbE, Cd 41/42 (–TTCT), IVS 1–1 (G–T), and IVS 1–5 (G–C) were the most common mutations, accounting for 81.4%, whereas Cd 41/42 (–TTCT) and IVS 2–654 (C–T) were most common among the Chinese (79.1%). Conclusion: We propose the use of this cheap, easy to interpret, and simple system for the molecular diagnostics of β-thalassaemia among Malaysians at the Institute for Medical Research (IMR)