Killer cell immunoglobulin-like receptor genotypes in Behçet's disease patients: any role for the 3DP1*001/002 pseudogene?

AIMS: Genotypic profiles of the natural killer cell immunoglobulin-like receptors (KIR) have been reported to vary among different ethnic groups and variable clinical entities. This study represents the second report on its distribution among patients with Behçet's disease (BD). We studied 43 unrelated Lebanese Behçet's patients, had their DNA typed using sequence-specific primer technique for the presence of 16 KIR genes and pseudogenes loci, and compared them to the general Lebanese population. RESULTS: In addition to sharing common features with the general population, the AA genotype was still the most frequent--however, with five new KIR profiles identified. There was no statistically significant distribution of the different KIR genes between the cases (BD patients) and controls (Lebanese population); however, KIR3DP1*001/002 was found to be significantly different between the BD patients and the Lebanese population, but this significance was lost after correction for all KIR loci. CONCLUSION: The results lead to an interesting future research question of whether or not KIR genotype is involved in the predisposition to or pathogenesis of BD especially that a pseudogene is controversially in question. This is the second report that describes the KIR genotypic profile in such an important clinical disease but the first to shed a light on the possible role of a pseudogene.

Distribution of killer cell immunoglobulin-like receptor (KIR) genotypes in patients with familial Mediterranean fever.

Genotypic profiles of the natural killer cell immunoglobulin-like receptors (KIR) have been reported to vary among different ethnic groups and variable clinical entities. This study represents the first report on its distribution among patients with familial Mediterranean fever (FMF). We studied 56 unrelated Lebanese FMF patients, had their DNA typed using sequence-specific primer (SSP) technique for the presence of 16 KIR gene and pseudogene loci, and compared them to the general Lebanese population. The AA1 genotype was the most frequent in both the FMF and control groups. Six new KIR profiles were identified. The FMF group showed a higher prevalence of KIR 3DP1*003 (p<0.05) and an increase in the BB genotype compared with controls. The results lead to an interesting future research question of whether or not KIR genotype is involved in the predisposition to or pathogenesis of FMF. This is the first report that describes the KIR genotypic profile in this important clinical disease.

Prevalence of the prothrombin G20210A polymorphism in the Lebanese population: use of a reverse hybridization strip assay approach.

The factor II (prothrombin) G20210A gene polymorphism is the second most common SNP reported in VTE where it is associated with elevated plasma prothrombin levels and with a 3-fold increased risk. We studied the distribution of the G/G, G/A, and A/A genotypes of the Prothrombin G20210A gene mutation in the general Lebanese population using a novel technique in order to assess their prevalence, compare the results to previously reported data and to describe an available method that will permit easy and fast identification of the mutation. Prothrombin different genotypes were determined using the Cardiovascular Disease (CVD) StripAssay which is based on a Polymerase Chain Reaction-Reverse hybridization technique and DNA from 205 unrelated healthy donors from our HLA-bank was used. The prevalence of G/G, G/A, and A/A genotypes was found to be 98.54, 1.46, and 0%, respectively, with G and A allelic frequency of 99 and 1%, respectively. The sampled Lebanese population showed prothrombin genotypes distribution similar to Caucasians, and our results are comparable to other reports on the Lebanese healthy individuals. However, this is the first report on the prevalence of prothrombin G20210A mutation using this technique. Our results suggest that this approach is reliable and can be used as an assessment for thrombophilia profile. In addition, future investigations should be conducted to assess the contribution of the prothrombin G20210A mutation, on its own and in collaboration with other factors, in various clinical entities notably VTE.

High prevalence of MTHFR gene A1298C polymorphism in Lebanon.

BACKGROUND: Mutations in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene could reduce the enzyme activity and lead to hyperhomocysteinemia, a condition that has been associated with several vascular conditions, in particular, coronary artery disease and deep vein thrombosis. AIM: The aim of this study was to assess the prevalence of the two most common polymorphisms, C677T and A1298C, which have not been well studied in the Lebanese population. METHODS: We randomly selected 205 healthy individuals originating from different Lebanese provinces and religious communities. The CVD StripAssay was used to test for MTHFR gene polymorphisms. RESULTS: We found that for C677T, the prevalence of C/C, C/T, and T/T genotypes was 65.3%, 30.8%, and 3.9%, respectively, with an overall carrier rate of 34.6% and allelic frequency of 0.19. However, the A1298C genotypic prevalence of A/C, A/A, and C/C was 50.2%, 25.9%, and 23.9%, respectively, with an overall carrier rate of 74.14% and an allelic frequency of 0.49. CONCLUSIONS: Compared to all other populations reported so far, the Lebanese population harbors the highest prevalence of the MTHFR A1298C polymorphism. This is an important finding to be followed in terms of clinical significance and sheds light on an additional unique genetic feature in this community.

Plasminogen Activator Inhibitor-1 (PAI-1) gene 4G/5G alleles frequency distribution in the Lebanese population.

Plasminogen activator inhibitor-1 (PAI-1) is an inhibitor of fibrinolysis. Increased plasma PAI-1 levels play an essential role in the pathogenesis of cardiovascular risk and other diseases associated with thrombosis. The 4G/5G polymorphism of the PAI-1 promoter region has been extensively studied in different populations. We studied 160 healthy unrelated Lebanese individuals using a reverse hybridization PCR assay to detect the 5G/5G, 4G/5G and, 4G/4G genotypes of the PAI-1 gene and the frequencies of the 4G and 5G alleles. We found that 4G/5G genotype was the most prevalent (45.6%) followed by 5G/5G (36.9%) and 4G/4G (17.5%). The frequencies of the 4G and 5G alleles were calculated to be 0.403 and 0.597, respectively. Compared to other ethnic communities, the Lebanese population was found to harbour a relatively high prevalence of the rare 4G allele. This, in turn, may predispose this population to develop cardiovascular diseases and other thrombotic clinical conditions. This study aids to enhance our understanding of the genetic features of the Lebanese population.

MEFV gene mutations spectrum among Lebanese patients referred for Familial Mediterranean Fever work-up: experience of a major tertiary care center.

Familial Mediterranean Fever (FMF) is an autosomal recessive inflammatory disorder predominantly affecting people living in or originating from areas around the Mediterranean Sea, mainly Jews, Armenians, Turks, and Arabs. It is characterized by recurrent attacks of inflammation of serosal membranes and fever resulting in acute abdominal, chest, or joint pain. Over 50 MEditerranean FeVer (MEFV) mutations and polymorphisms have been identified in FMF patients. The objective of this study was to analyze the distribution and frequencies of 12 MEFV mutations in 266 referred Lebanese patients using a reverse-hybridization assay. Of the 266 patients, 129 (48.5%) were positive for at least one mutation and 137 (51.5%) had no mutations detected. Of the 129 patients with mutations, 35 were homozygous, 41 were compound heterozygous and 53 were heterozygous. The five most common mutations M694V, E148Q, V726A, M694I and M680I (G/C) accounted for 26.1, 22.2, 21.3, 9.6 and 7.7%, respectively. The A744S, F479L, R761H and I692del were encountered in 2.9% of patients; P369S and M680I (G/A) were found in 1.2% of patients while K695R was absent. The spectrum of the MEFV mutations among our sampled Lebanese FMF patients shows the high heterogeneity at the allelic level when compared to Arab and non-Arab populations. The most important feature was the relatively high frequency of the E148Q in our study group that allows us to question it as a mutation rather than a polymorphism. Further studies should be conducted to evaluate the role of the E148Q allele.

Frequency distribution of the G/A alleles of the beta-fibrinogen gene in the Lebanese population.

Fibrinogen is a plasma protein that has been reported to be associated with an increased risk of atherothrombotic diseases and venous thrombosis. The most common polymorphism that has been studied so far in different populations is the G-455-->A polymorphism in the promoter region of the beta-fibrinogen gene. We studied 160 healthy unrelated Lebanese individuals for the prevalence of -455G/G, -455G/A and -455A/A genotypes of the beta-fibrinogen gene and the frequency of G and A alleles using a reverse hybridization PCR assay. The prevalence of the G/G, G/A, and A/A genotypes were found to be 60.6, 31.9 and 7.5%, respectively. The frequency of the G and A alleles were found to be 0.77 and 0.23, respectively. As compared to other ethnic groups, the Lebanese individuals were found to have a relatively high prevalence of the A allele which may predispose them to develop cardiovascular diseases as well as thrombotic events. This study provides additional unique genetic information pertaining to the Lebanese population.

Factor XIII gene V34L mutation in the Lebanese population: another unique feature in this community?

We studied the distribution of the Factor XIII gene V34L polymorphism in a sample of healthy Lebanese individuals to assess its prevalence and compare it with other populations. Factor XIII genotypes were determined using the Cardiovascular Disease (CVD) StripAssay (ViennaLab, Austria), which is based on a Polymerase Chain Reaction-Reverse hybridization technique. DNA from 205 unrelated healthy donors from our HLA database was used. The prevalence of Wild type, heterozygous, and homozygous genotypes was found to be 74.2%, 22.4%, and 3.4% respectively. The sampled Lebanese population showed that the prevalence of V34L carriers (25.8%) was lower than Caucasians in general (44.3%) and, interestingly, with a low allele frequency of 0.14 similar to that in Blacks and South Asians. This first report from Lebanon sheds light on an additional unique genetic feature of this population and will prospectively serve as a baseline statistical data for future investigations of the prevalence of Factor XIII V34L mutation in association with various clinical entities notably cardiovascular diseases.

The advantages of submandibular gland resection in anterior retropharyngeal approach to the upper cervical spine.

Anterior surgery to the upper cervical spine, although rare, several successful approaches were described in the literature. To avoid the risks and limitations of transoral approach, the anterior retropharyngeal approach was developed. In this study, we describe our experience with anterior retropharyngeal approach to the upper cervical spine and discuss the significance of resecting the submandibular gland. From July 2001 to July 2004, we performed six anterior prevascular retropharyngeal approaches to the upper cervical spine. The series included five males and one female, ranging in age from 26 to 60 years (mean = 46). All six patients were intubated with nasotracheal cannula. The submandibular gland was mobilized and removed in all patients allowing adequate exposure of the arch of C1, C2, and C3 vertebral bodies. The anterior retropharyngeal approach permitted an adequate access to anteriorly situated lesions from C1 to C3 in all six patients, without the risks and limitations of transmucosal surgery. This approach allowed us to perform decompression of the spinal cord and reconstruction of the anterior column of the spine with bone graft and internal fixation. Careful removal of the submandibular gland provided better visualization of the arch of C1 and C2. No facial nerve palsy was seen in any of the six patients. Anterior retropharyngeal approach to the upper cervical spine combined with removal of the submandibular gland permits exposure of the anterior spine similar to that obtained by the transmucosal route, and provides a safe simultaneous arthrodesis and instrumentation during the primary surgical procedure without the potential contamination of the oropharyngeal cavity. Removal of the submandibular gland allows better exposure with less retraction and thus avoids severe injury to the mandibular branch of the facial nerve.

ApoB-100 R3500Q mutation in the Lebanese population: prevalence and historical review of the literature.

An interesting mutation affecting the Apo-B gene, R3500Q, is known to display variable geographical distribution in the world and is mostly implicated in the pathogenesis of Familial Hypercholesterolemia (FH). The aim of this study is to determine the prevalence of this mutation in the Lebanese population and compare it to the available international literature. DNA from 160 unrelated healthy donors from our HLA-bank was used and the ApoB genotype was determined using the CardioVascular Disease (CVD) StripAssay (this assay is based on a Polymerase Chain Reaction-Reverse Hybridization technique). The R3500Q mutation was not observed in the general Lebanese population. Since the mutation frequency is elevated in Central Europe and tends to decrease as one moves east and south, it disappears completely in the Mediterranean regions such as Spain, Turkey and Israel; therefore, it is rather expected to be absent in Lebanon as well. Our report adds a valuable piece of information regarding this mutation in an Arab country and paves the way for future research involving patients diagnosed with FH in order to assess the role of the R3500Q mutation in the development of this clinical entity.

Angiotensin-converting enzyme gene polymorphism and allele frequencies in the Lebanese population: prevalence and review of the literature.

We studied the distribution of the D/D, I/D, and I/I genotypes of the angiotensin-converting enzyme (ACE) in a sample of healthy Lebanese individuals to assess their prevalence and compare them with other populations. ACE genotypes were determined using the Cardiovascular Disease (CVD) StripAssay, which is based on a Polymerase Chain Reaction-Reverse hybridization technique. DNA from 133 unrelated healthy donors from our HLA-bank was used. The prevalence of D/D, I/D, and I/I genotypes was found to be 39.1, 45.1, and 15.8% respectively, with D and I allelic frequency of 61.7 and 38.3%, respectively. The sampled Lebanese population showed ACE genotypic distributions similar to Caucasians; however, with tendency towards harboring high D allele frequency together with a low I allele frequency just like the Spanish population. This first report from Lebanon will serve as a baseline statistical data for future investigations of the prevalence of ACE genotypes in association with various clinical entities notably cardiovascular diseases. The medical literature was also reviewed in this context.

Prevalence of factor V R2 (H1299R) polymorphism in the Lebanese population.

AIMS: A recently identified polymorphism in factor V gene (His1299Arg; also named HR2) has been reported to be a possible risk factor for the development of venous thromboembolism (VTE), with a high prevalence of 9.5-15.2% in patients of different ethnic groups in different parts of the world. The aim of this study is to assess the prevalence of HR2 haplotype in Lebanon. METHODS: We randomly selected 125 samples from unrelated donors logged into our HLA registry; these represent healthy Lebanese individuals originating from different provinces and religious communities of the country. Their DNA was extracted using the Pel-Freez extraction kit and stored at -80 degrees C for later use. The CVD StripAssay was used for PCR and reverse hybridisation. It screens for several gene mutations including factor V H1299R. RESULTS: A total of 125 controls were studied: 72 males and 53 females with a median age 42 years. Thirteen (10.4%) had the HR2 haplotype; 11 (8.8%) were heterozygous (R1/R2), and two (1.6%) were homozygous (R2/R2), with an allelic frequency of 0.06. CONCLUSIONS: Our study is the first report from Lebanon that describes the prevalence of HR2 haplotype and the frequency of its alleles. We are reporting a high prevalence of the HR2 in our population (10.4%). The hypothesis that A4070G polymorphism might contribute to the expression of a thrombotic phenotype deserves to be tested in our population through larger studies.

Apolipoprotein E gene polymorphism and allele frequencies in the Lebanese population.

Apolipoprotein E (ApoE) genotypes were studied in order to determine the prevalence in the Lebanese population and compare it with other populations. DNA from 160 unrelated healthy donors from our HLA-bank was used. ApoE genotype was determined using the CardioVascular Disease (CVD) StripAssay (this assay is based on a Polymerase Chain Reaction-Reverse Hybridization technique). The prevalence of genotypes E3/3, E3/4, and E2/3 was found to be 69%, 26%, and 22%, respectively, and 0.6% for each of E2/4 and E4/4 genotypes. The Lebanese population tested showed similarities to earlier reported ApoE genotypic distributions (high E3 allele frequency) but also peculiar differences especially to some Arabic countries (total absence of E2 allele among Saudis) and other populations. This is the first report from Lebanon that will serve as a template for future investigations of the prevalence of ApoE alleles in association with various clinical entities.

Filariasis infection is a probable cause of implantation failure in in vitro fertilization cycles.

OBJECTIVE: To describe a parasitic infection that probably affected the implantation of good-quality embryos in an in vitro fertilization (IVF) cycle. DESIGN: Case report. SETTING: Tertiary care center in a university hospital. PATIENT(S): A 36-year-old Caucasian female with primary unexplained infertility. The patient underwent two cycles of IVF with good-quality embryos transferred; however, no pregnancy ensued despite adequate luteal support. INTERVENTION(S): In vitro fertilization cycles, CBC, blood smear, evaluation for eosinophilia including serological evaluation for parasitic infections. MAIN OUTCOME MEASURE(S): Pregnancy. RESULT(S): Following treatment for filariasis, a repeat IVF cycle using the same stimulation protocol yielded a full-term pregnancy. CONCLUSION(S): This case is of particular importance because, to our knowledge, it is the first to describe a parasitic infection that probably affected the implantation of good-quality embryos in IVF cycles.

Aneurysmal bone cyst of the cervical spine in a child: case report and review of the surgical role.

BACKGROUND: Surgical treatment of aneurysmal bone cysts of the cervical spine, frequently affecting pediatric patients, is a challenge to operating surgeons. Complete tumor resection offers the best chance for cure. CASE DESCRIPTION: We present the case of a child with an expansile aneurysmal bone cyst of the cervical spine that involves all 3 spinal columns. The advantages of combining a posterolateral followed by anterior approach after a preoperative angiography and vertebral artery balloon occlusion testing provided the added safety to maximize the extent of tumor resection. Spinal stabilization was successfully achieved in both approaches. CONCLUSION: The challenge of surgically resecting aneurysmal bone cysts of the cervical spine in children enabled us to achieve a total resection with the help of preoperative angiography and vertebral artery balloon occlusion testing. Spinal instability should be addressed with reconstruction and stabilization techniques.