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Classification of suprabullar pneumatization according to the skull base attachment of the second lamella

Tan KL, Lee WH, Kim JW

Eur Arch Otorhinolaryngol, 2017 Jan;274(1):223-229.
PMID: 27423641 DOI: 10.1007/s00405-016-4201-4

The skull base attachment of the second lamella and suprabullar pneumatization are likely to be consistent landmarks if they are systematically classified. This study aimed to classify the pneumatization pattern according to the second lamella skull base attachment. A total of 202 computed tomography sides of 101 patients who underwent endoscopic sinus surgery were studied. Suprabullar pneumatization was defined as air cells present above the ethmoid bulla between the second and third lamellae. Its pattern was classified according to the air cell number and location as in the frontal cell classification. Type 0 suprabullar pneumatization was defined as no air cells between the ethmoid bulla and skull base; type 1, as a single suprabullar cell; and type 2, as multiple suprabullar cells above the ethmoid bulla. In type 3 pneumatization, the second lamella extended into the frontal sinus forming a frontal bullar cell. Type 2 was the most prevalent (40.1 %), followed by types 1, 3, and 0 (24.3, 23.3, and 12.4 %, respectively). The distance between the second lamella and anterior ethmoid artery was 8.93, 8.30, 8.50, and 11.25 mm in types 0, 1, 2, and 3 pneumatization, respectively. No patients had intraoperative injuries in the anterior ethmoid artery or lateral lamella. The second lamella skull base attachment and suprabullar pneumatization pattern could be systematically classified and be a consistent landmark to identify the frontal sinus opening.
Index of suspicion with appropriate timing of CT scan helps prevent missed diagnosis in urologic trauma

Sabrina B, Tan KL, Johann FK, Andre D

Med J Malaysia, 2018 08;73(4):255-256.
PMID: 30121691 MyJurnal

Ureteric and bladder injuries are uncommon, difficult to diagnose and rarely occur in isolation. Diagnosis is often delayed or missed at presentation. Therefore, high clinical suspicion and appropriate timing of computed tomography (CT) are of paramount importance. We report two cases (ureteropelvic junction avulsion and ruptured dome of bladder) whereby the presentations were subtle and would have been missed if not for high clinical suspicion. This article discusses the problems associated with these urologic injuries, as well as how to develop a high index of suspicion based on the pattern of anatomical disruption, mechanism of injury, physiological abnormality and comorbidity.
Fulltext Demographic Factors Associated With Public Awareness of Chiropractic in Klang Valley, Malaysia: A Cross-sectional Study

Wong YK, Tan KL, Haneline MT

J Chiropr Med, 2022 Sep;21(3):187-196.
PMID: 36118112 DOI: 10.1016/j.jcm.2022.02.020

OBJECTIVE: The purposes of this study were to determine the public awareness of chiropractic in Klang Valley and to identify sociodemographic factors associated with this awareness.
METHODS: A cross-sectional study with a total of 440 respondents was conducted in medical, chiropractic, pharmacy, and dental health care facilities in Klang Valley. A self-administrated questionnaire was enclosed in an envelope and handed to the participants by the health care facilities' staff. Tables and figures were used to present the descriptive data. Data collected were also analyzed using inferential statistics such as binary logistic regression, odds ratio, and 95% confidence interval. The variables in this study were age, ethnicity, sex, education level, marital status, nationality, employment status, and health status along with awareness of chiropractic.
RESULTS: The respondents' ages ranged from 18 to 81 years, and the mean age was 33.1 years. The majority of respondents were single (52.1%), and 43.1% of respondents were married. Most of the respondents were employed (64.4%), followed by students (14.8%). Among the respondents, 40.2% perceived to have a good health status. Good awareness of chiropractic was 50.2%, whereas the poor awareness of chiropractic was 49.8%. Two sociodemographic factors that were statistically significantly associated with the awareness of chiropractic were ethnicity and employment status, with a P value of
Fulltext Chiropractic Utilization Among Patients in Klang Valley, Malaysia

Wong YK, Tan KL, Haneline MT

J Chiropr Med, 2020 Sep;19(3):159-166.
PMID: 33362438 DOI: 10.1016/j.jcm.2019.10.003

OBJECTIVE: The purpose of this study was to estimate the utilization of chiropractic in Klang Valley, Malaysia.
METHODS: This research was a cross-sectional study conducted in 4 health care centers, namely Klinik Mediviron Sri Rampai, Queck Dental Surgery, International Medical University (IMU) Healthcare Chiropractic Centre, and Be Pharmacy Bandar Sri Permaisuri, in Klang Valley from July to November 2018, with a total of 440 respondents. The data collection was done by the self-administration method using questionnaires that were enclosed in envelopes and passed on to the participants by the center's staff. Descriptive statistics were conducted on the data collected and are presented in tables and figures. The variables were sex, age, nationality, ethnicity, marital status, education level, employment status, and health status with the utilization of chiropractic.
RESULT: There were 186 (42.3%) male and 254 (57.7%) female respondents. The youngest respondent was 18 years old, and the oldest was 81 years old. The median age was 30 years old. Most respondents (97.3%) were Malaysian from a non-Bumiputra (non-Malay) ethnic group. Almost half (47.5%) of the respondents had a bachelor's degree education level. The utilization of chiropractic was 35.9% (95% confidence interval [CI]: 31.4-40.5).
CONCLUSION: The utilization of chiropractic was 35.9%, which was slightly lower than utilization among other traditional and complementary medicine practices in Malaysia.
Public Awareness of the Traditional and Complementary Medicine Act Governing Chiropractic in Malaysia: A Survey of Adults in Klang Valley

Wong YK, Haneline MT, Tan KL

J Chiropr Humanit, 2023 Dec;30:16-22.
PMID: 37822922 DOI: 10.1016/j.echu.2023.08.002

OBJECTIVE: This study aimed to assess the level of awareness of the traditional and complementary medicine law governing chiropractic among adults in Klang Valley, Malaysia.
METHODS: A cross-sectional study was conducted of patients attending the following 4 health care services: medicine, dentistry, pharmacy, and chiropractic. The study ran from July to November 2018. Data were collected through self-administered questionnaires and reported using descriptive statistics. Variables included demographic characteristics and awareness of the Traditional and Complementary Medicine Act 2016 (Act 775).
RESULTS: We obtained 440 responses, 186 (42.3%) from men and 254 (57.7%) from women, with ages ranging from 18 to 81 years. The majority of respondents (97.3%) were Malaysian from the non-Malay ethnic group. Almost half (47.5%) of the respondents had a bachelor's degree. The awareness of the traditional and complementary medicine law governing chiropractic was low (4.8%). Binary logistic regression revealed marital status as the only significant predictor of awareness of the Traditional and Complementary Medicine Act, with married individuals showing higher awareness (adjusted odds ratio: 2.77; 95% CI, 1.38-5.58).
CONCLUSION: For this sample of adults, the awareness of the Traditional and Complementary Medicine Act 2016 governing chiropractic was found to be low. As the regulation of chiropractic is still new in Malaysia and other Asian countries, efforts are needed to increase public awareness to ensure the safety and quality of chiropractic services.
Method development and validation for the simultaneous determination of imatinib mesylate and N-desmethyl imatinib using rapid resolution high performance liquid chromatography coupled with UV-detection

Tan KL, Ankathil R, Gan SH

J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Nov 15;879(30):3583-91.
PMID: 22000961 DOI: 10.1016/j.jchromb.2011.09.048

We developed a simple and sensitive method for the simultaneous detection of imatinib mesylate (IM) and its active metabolite, N-desmethyl imatinib (M1), in human serum samples. Separation was successfully achieved using an Agilent(®) ZORBAX Eclipse plus C(18) reversed phase column (50 mm × 2.1 mm, i.d.; 1.8 μm) under isocratic mobile phase conditions consisting of acetonitrile: 0.02 M potassium dihydrogen phosphate with 0.2% triethylamine at pH 3 (25:75, v/v) and ultra-violet detection was achieved at 235 nm. Extraction of the target compounds was completed using 100% cold acetonitrile. Good linearities (r(2)>0.99) for both IM and M1 were achieved for the concentration ranges of 50-1800 ng/mL and 50-360 ng/mL, respectively. The detection limits were 20 ng/mL and 10 ng/mL for M1 and IM, respectively. The intra- and inter-day precisions were less than 1% with percent recoveries of more than 90%. The method was successfully applied to calculate the pharmacokinetic parameters of chronic myeloid leukemia patients receiving imatinib. The method is suitable to be routinely applied for determination of IM and M1 in serum.
Fulltext Harvesting the maximum length of sciatic nerve from adult mice: a step-by-step approach

Bala U, Tan KL, Ling KH, Cheah PS

BMC Res Notes, 2014;7:714.
PMID: 25304607 DOI: 10.1186/1756-0500-7-714

Over the past several decades, many studies concerning peripheral nerve damage or regeneration have been performed. Mice have been widely used for many of these studies, with the sciatic nerve being the most targeted and preferred nerve. Therefore, techniques for harvesting mouse sciatic nerves of a maximum length that is sufficient for different analyses will be highly valuable. Here we describe a simple step-by-step guide for harvesting the maximum length of mouse sciatic nerve and compare the length of the harvested nerves gathered with the proposed method with nerves obtained using a conventional mid-thigh incision approach.
Iatrogenic tracheal flap mimicking tracheal stenosis with resultant stridor

Tan KL, Chong AW, Amin MA, Raman R

J Laryngol Otol, 2012 Jul;126(7):751-5.
PMID: 22578299 DOI: 10.1017/S0022215112000795

To illustrate a case of an iatrogenic mucosal tear in the trachea which caused a one-way valve effect, obstructing the airway and manifesting as post-extubation stridor.
Fulltext Characterisation of beta-globin gene mutations in Malaysian children: a strategy for the control of beta-thalassaemia in a developing country

Thong MK, Tan JA, Tan KL, Yap SF

J Trop Pediatr, 2005 Dec;51(6):328-33.
PMID: 15967770 DOI: 10.1093/tropej/fmi052

beta-thalassaemia major, an autosomal recessive hemoglobinopathy, is one of the most common single gene disorders in multi-racial Malaysia. The control of beta-thalassaemia major requires a multi-disciplinary approach that includes population screening, genetic counselling, prenatal diagnosis and the option of termination of affected pregnancies. To achieve this objective, the molecular characterisation of the spectrum of beta-globin gene mutations in each of the affected ethnic groups is required. We studied 88 consecutive unrelated individuals and their respective families with beta-thalassaemia (74 beta-thalassaemia major, 12 HbE-beta-thalassaemia, 2 with HbE homozygotes) and four individuals with beta-thalassaemia trait that contributed a total 180 alleles for study. Using a 2-step molecular diagnostic strategy consisting of amplification refractory mutation system (ARMS) to identify the 8 most common mutations followed by other DNA-based diagnostic techniques, a total of 177 (98.3 per cent) of the 180 beta-thalassaemia alleles were characterised. One out of 91 (1 per cent) of the Chinese alleles, one out of 46 (2.2 per cent) Malay alleles and one out of two Indian alleles remained unknown. A 100 per cent success rate was achieved in studying the Kadazandusun community in this study. A strategy to identify beta-globin gene mutations in Malaysians with beta-thalassaemia is proposed based on this outcome.
Immunolabelling of prolactin at ultrastructural level using the protein A-gold technique on Epon-embedded tissue

Ng KH, Tan KL, Gan SK, Looi LM

Malays J Pathol, 1992 Jun;14(1):29-33.
PMID: 1469915

The use of the colloidal-gold technique in electron microscopy immunocytochemistry has provided important information on the in situ localisation of intracellular antigens. We have developed a post-embedding technique for prolactin localisation on resin-embedded human pituitary tissue sections by the use of the protein-A gold conjugate. Human pituitary tissue obtained at autopsy was processed for electron microscopical study without post-osmication and then embedded in Epon. The indirect immunoperoxidase method was used for light microscopical targetting of lactotroph cells for subsequent electron microscopical antigen localisation. Ultra-thin sections were labelled with human anti-human prolactin followed by protein-A gold conjugate. Specific labelling was observed over secretory granules with a density of 15-30 particles per granule, as determined by the Quantimet 570 image analysis system. This technique provides a means of studying the pathophysiology of hormonal secretion at ultrastructural level and can be a useful tool in diagnostic and research investigations.
Fulltext Novel technique using amplatzer AVP I stent in management for giant renal artery pseudoaneurysm

Sarmukh S, Putera MP, Tan KL, Chew LG

Urol Case Rep, 2021 Mar;35:101515.
PMID: 33318942 DOI: 10.1016/j.eucr.2020.101515

Renal artery pseudoaneurysm (RAP) is an uncommon vascular lesion. Early detection and treatment of renal artery pseudoaneurysm is important because it can rupture and lead to life-threatening hemorrhage. Recent advances in endovascular interventions can prevent potentially challenging open surgery. We describe a case 66 year old patient who presented with a painful abdominal lumbar mass. CT scan show a giant renal artery pseudoaneurysm. We discuss management of giant renal artery pseudoaneurysm, both open surgery and endovascular surgery. Endovascular arterial embolization and stent techniques is feasible. However, open surgical treatment remains to be most effective and radical method in emergency setting.
An immunohistochemical method for the diagnosis of melioidosis

Wong KT, Vadivelu J, Puthucheary SD, Tan KL

Pathology, 1996 May;28(2):188-91.
PMID: 8743829

In order to assess the usefulness of immunohistochemistry in the diagnosis of melioidosis, an infection by Burkholderia pseudomallei, polyclonal antibodies were applied to tissues from known cases of melioidosis and to other infected tissues. Formalin-fixed, paraffin-embedded tissues were stained by a modified immunoperoxidase technique. In autopsy tissues with inflammatory lesions of melioidosis, the cytoplasm of phagocytes and intact bacilli, both intra- and extracellular, were stained very strongly positive. Relatively more focal positive staining was observed in some but not all surgical biopsies from proven cases of melioidosis. In granulomas staining was mainly found in the central necrotic areas, with little staining of peripheral phagocytes. All control materials stained negative. Immunohistochemistry appears to be a useful diagnostic tool in melioidosis.
Fulltext Pre-auricular sinus: an uncommon presentation

Ng JWS, Chew YK, Tan KL, Chong AW

Malays Fam Physician, 2011;6(1):32-33.
PMID: 25606218 MyJurnal

An infected pre-auricular sinus presenting as a post-auricular swelling is commonly misdiagnosed as an infected dermoid or sebaceous cyst. It may even mimic a mastoid abscess leading to further unwarranted investigations and interventions. We present a case of a 25-year-old Malay man who was initially diagnosed with recurrent infected dermoid cyst. At presentation, a right post-auricular inflamed swelling was noted with an overlying old incision and drainage scar. An auricular pit was found at the crus of helix. Using a blunt probe inserted along the sinus tract pus was drained without the need for further surgical incision. Six weeks after the acute episode, patient underwent excision of the pre-auricular sinus with no evidence of recurrence at three months follow up. Awareness by the attending physician of this ‘variant type’ of pre-auricular sinus at patient’s first presentation may negate the need for unnecessary incision and drainage which may subsequently impact the outcome of surgical excision and reduce the risk of recurrence.
Mitochondrial Dysfunction in Down Syndrome: From Pathology to Therapy

Tan KL, Lee HC, Cheah PS, Ling KH

Neuroscience, 2023 Feb 10;511:1-12.
PMID: 36496187 DOI: 10.1016/j.neuroscience.2022.12.003

Mitochondrial dysfunctions have been described in Down syndrome (DS) caused by either partial or full trisomy of chromosome 21 (HSA21). Mitochondria play a crucial role in various vital functions in eukaryotic cells, especially in energy production, calcium homeostasis and programmed cell death. The function of mitochondria is primarily regulated by genes encoded in the mitochondrion and nucleus. Many genes on HSA21 are involved in oxidative phosphorylation (OXPHOS) and regulation of mitochondrial functions. This review highlights the HSA21 dosage-sensitive nuclear-encoded mitochondrial genes associated with overexpression-related phenotypes seen in DS. This includes impaired mitochondrial dynamics, structural defects and dysregulated bioenergetic profiles such as OXPHOS deficiency and reduced ATP production. Various therapeutic approaches for modulating energy deficits in DS, effects and molecular mechanism of gene therapy and drugs that exert protective effects through modulation of mitochondrial function and attenuation of oxidative stress in DS cells were discussed. It is prudent that improving DS pathophysiological conditions or quality of life may be feasible by targeting something as simple as cellular mitochondrial biogenesis and function.
Fulltext Leucine-Rich Alpha-2-Glycoprotein: A Novel Predictor of Diastolic Dysfunction

Loch A, Tan KL, Danaee M, Idris I, Ng ML

Biomedicines, 2023 Mar 20;11(3).
PMID: 36979923 DOI: 10.3390/biomedicines11030944

Leucine-rich α2-glycoprotein (LRG1) mediates cardiac fibrocyte activation. It is upregulated in inflammatory conditions, atherosclerosis, and fibrosis. Diastolic dysfunction (DD) is due to myocardial fibrosis. This cross-sectional study examined the relationship between LRG1 and DD. Patients with symptoms of chronic coronary ischemia were recruited. Patients with symptoms of overt heart failure, ejection fraction (EF) < 55%, impaired renal function, infection, and recent trauma were excluded from the study. Clinical parameters examined were SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery (SYNTAX) score, echocardiographic assessment, and LRG1 levels. Binary stepwise logistic regression was used to evaluate the association between LRG1 and DD. Receiver Operating Characteristic (ROC) analysis was used to determine optimal cut-off values and predictive performance of LRG1. A total of 94 patients were enrolled in the study, with 47 having a clinical diagnosis of DD. Plasma LRG1 was significantly (U = 417.00, p < 0.001) higher in the DD group (M = 14) compared to the No-DD group (M = 8) by Mann-Whitney U test. There were higher SYNTAX scores in the DD group (M = 24.5) compared with No-DD (M = 7). LRG1 had significant predictability of DD (OR = 1.32 (95% CI: 1.14-1.53)). The ROC showed an AUC = 0.89 (95% CI: 0.82-0.95). LRG1 had a 78% sensitivity (95% CI: 65.3-87.7) and 72.3% specificity (95% CI: 57.4-84.4) for predicting DD at a cut-off value of "9". In conclusion, we identified LRG1 as a novel independent predictor of DD. Further studies are warranted to validate the utility of LRG1 in predicting DD.
Fulltext Potential Role of JAK-STAT Signaling Pathway in the Neurogenic-to-Gliogenic Shift in Down Syndrome Brain

Lee HC, Tan KL, Cheah PS, Ling KH

Neural Plast, 2016;2016:7434191.
PMID: 26881131 DOI: 10.1155/2016/7434191

Trisomy of human chromosome 21 in Down syndrome (DS) leads to several phenotypes, such as mild-to-severe intellectual disability, hypotonia, and craniofacial dysmorphisms. These are fundamental hallmarks of the disorder that affect the quality of life of most individuals with DS. Proper brain development involves meticulous regulation of various signaling pathways, and dysregulation may result in abnormal neurodevelopment. DS brain is characterized by an increased number of astrocytes with reduced number of neurons. In mouse models for DS, the pool of neural progenitor cells commits to glia rather than neuronal cell fate in the DS brain. However, the mechanism(s) and consequences of this slight neurogenic-to-gliogenic shift in DS brain are still poorly understood. To date, Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling has been proposed to be crucial in various developmental pathways, especially in promoting astrogliogenesis. Since both human and mouse models of DS brain exhibit less neurons and a higher percentage of cells with astrocytic phenotypes, understanding the role of JAK-STAT signaling in DS brain development will provide novel insight into its role in the pathogenesis of DS brain and may serve as a potential target for the development of effective therapy to improve DS cognition.
An epidemiological study of developmental dysplasia of the hip in infants in Singapore

Ang KC, Lee EH, Lee PY, Tan KL

Ann Acad Med Singap, 1997 Jul;26(4):456-8.
PMID: 9395810

The incidence of congenital dislocation of the hip (CDH) in Singapore and Malaysia has been reported as being lower than in the West. In our hospital, we have seen an increasing number of congenital hip dislocation as well as dysplastic hips. We undertook a prospective study from December 1989 to December 1994 of 20,000 live births. The neonates were all screened by a consultant neonatologist and the findings were confirmed by a consultant paediatric orthopaedic surgeon. All babies had plain X-rays at 3 months and an acetabular index (AI) of 30 degrees or more was considered dysplastic. All babies with positive signs were followed up for 1 year and again had radiographs taken at 1 year. Comparison of plain X-rays and ultrasound assessment in a subgroup of 130 neonates showed that 64% of patients with AI > 20 degrees had hip dysplasia by ultrasonographic (alpha angle < 60 degrees) The incidence of dysplastic hips was 16.8 per 1000 live births. The overall incidence of neonates with dislocated hips was 4.7 per 1000 live births. The Malays were most affected with an incidence of 5.4 per 1000 live births. The incidence of developmental dysplasia of the hip in Singapore is higher than previously reported, with the Malays having the highest incidence. A significant number of babies with clicking hips have radiological evidence of acetabular dysplasia (AI > 30 degrees). One-third of the babies' hips were still dysplastic at 1 year of age. A well-organised screening programme with experienced examiners has proved to be useful in making early and accurate clinical diagnosis.
Fulltext MicroRNAs and intellectual disability (ID) in Down syndrome, X-linked ID, and Fragile X syndrome

Siew WH, Tan KL, Babaei MA, Cheah PS, Ling KH

Front Cell Neurosci, 2013;7:41.
PMID: 23596395 DOI: 10.3389/fncel.2013.00041

Intellectual disability (ID) is one of the many features manifested in various genetic syndromes leading to deficits in cognitive function among affected individuals. ID is a feature affected by polygenes and multiple environmental factors. It leads to a broad spectrum of affected clinical and behavioral characteristics among patients. Until now, the causative mechanism of ID is unknown and the progression of the condition is poorly understood. Advancement in technology and research had identified various genetic abnormalities and defects as the potential cause of ID. However, the link between these abnormalities with ID is remained inconclusive and the roles of many newly discovered genetic components such as non-coding RNAs have not been thoroughly investigated. In this review, we aim to consolidate and assimilate the latest development and findings on a class of small non-coding RNAs known as microRNAs (miRNAs) involvement in ID development and progression with special focus on Down syndrome (DS) and X-linked ID (XLID) [including Fragile X syndrome (FXS)].
Chemopreventive potential of Annona muricata L leaves on chemically-induced skin papillomagenesis in mice

Hamizah S, Roslida AH, Fezah O, Tan KL, Tor YS, Tan CI

Asian Pac J Cancer Prev, 2012;13(6):2533-9.
PMID: 22938417

Annona muricata L (Annonaceae), commonly known as soursop has a long, rich history in herbal medicine with a lengthy recorded indigenous use. It had also been found to be a promising new anti-tumor agent in numerous in vitro studies. The present investigation concerns chemopreventive effects in a two-stage model of skin papillomagenesis. Chemopreventive effects of an ethanolic extract of A. muricata leaves (AMLE) was evaluated in 6-7 week old ICR mice given a single topical application of 7,12-dimethylbenza(α)anthracene (DMBA 100 μg/100 μl acetone) and promotion by repeated application of croton oil (1% in acetone/ twice a week) for 10 weeks. Morphological tumor incidence, burden and volume were measured, with histological evaluation of skin tissue. Topical application of AMLE at 30, 100 and 300 mg/kg significantly reduced DMBA/croton oil induced mice skin papillomagenesis in (i) peri-initiation protocol (AMLE from 7 days prior to 7 days after DMBA), (ii) promotion protocol (AMLE 30 minutes after croton oil), or (iii) both peri-initiation and promotion protocol (AMLE 7 days prior to 7 day after DMBA and AMLE 30 minutes after croton oil throughout the experimental period), in a dose dependent manner (p<0.05) as compared to carcinogen-treated control. Furthermore, the average latent period was significantly increased in the AMLE-treated group. Interestingly, At 100 and 300 mg/ kg, AMLE completely inhibited the tumor development in all stages. Histopathological study revealed that tumor growth from the AMLE-treated groups showed only slight hyperplasia and absence of keratin pearls and rete ridges. The results, thus suggest that the A.muricata leaves extract was able to suppress tumor initiation as well as tumor promotion even at lower dosage.
Fulltext Molecular characterisation and frequency of Ggamma Xmn I polymorphism in Chinese and Malay beta-thalassaemia patients in Malaysia

Wong YC, George E, Tan KL, Yap SF, Chan LL, Tan JA

Malays J Pathol, 2006 Jun;28(1):17-21.
PMID: 17694955

The molecular basis of variable phenotypes in P-thalassaemia patients with identical genotypes has been associated with co-inheritance of alpha-thalassaemia and persistence of HbF production in adult life. The Xmn I restriction site at -158 position of the Ggamma-gene is associated with increased expression of the Ggamma-globin gene and higher production of HbF This study aims to determine the frequency of the digammaferent genotypes of the Ggamma Xmn I polymorphism in P-thalassaemia patients in two ethnic groups in Malaysia. Molecular characterisation and frequency of the Ggamma Xmn I polymorphism were studied in fifty-eight Chinese and forty-nine beta-thalassaemia Malay patients by Xmn I digestion after DNA amplification of a 650 bp sequence. The in-house developed technique did not require further purification or concentration of amplified DNA before restriction enzyme digestion. The cheaper Seakem LE agarose was used instead of Nusieve agarose and distinct well separated bands were observed. Genotyping showed that the most frequent genotype observed in the Malaysian Chinese was homozygosity for the absence of the Xmn I site (-/-) (89.7%). In the Malays, heterozygosity of the Xmn I site (+/-) was most common (63.3%). Homozygosity for the Xmn I site (+/+) was absent in the Chinese, but was confirmed in 8.2% of the Malays. The ratio of the (+) allele (presence of the Xmn I site) to the (-) allele (absence of the Xmn I site)) was higher in the Malays (0.66) compared to the Chinese (0.05). The (+/-) and (+/+) genotypes are more commonly observed in the Malays than the Chinese in Malaysia.

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