Hereditary thrombophilia in ethnic Omani patients

Targeted next-generation sequencing reveals novel and known variants of thrombophilia associated genes in Saudi patients with venous thromboembolism

BACKGROUND

Thrombophilia is a substantial source of indisposition and mortality in several countries, including Arab populations. Deep venous thrombosis (DVT) with or without pulmonary embolism (PE) is the prevalent clinical manifestation of thrombophilia. While many genetic risk factors for DVT are known, almost all associated with hemostasis, many genetic factors remain unexplained. Nowadays, Next Generation Sequencing (NGS) offers a potential solution that allows several candidate genes to be analyzed simultaneously at a reasonable expense.

METHODS

We performed variant screening in the thrombophilia associated genes in Factor V Leiden (FVL) mutation-negative patients using Ion Torrent Next-generation sequencing (NGS). Ion AmpliSeq panel for 18 genes was designed. Twenty-nine unrelated patients with idiopathic VTE were recruited for NGS.

RESULTS

We were able to identify 19 variants (1 novel and 18 previously reported) in 10 out of 18 targeted genes. Pathogenic variants were identified in 22 patients demonstrating mutation detection rates of 76%. Previously reported variants in the F5, MTHFR, PROS1, PROC, F8, F9, SERPINA10, SERPIND1, and HRG genes were recognized in 21 patients. More than one variant in the targeted genes was detected in some of the patients with VTE. We identified SERPINA10 recurrent variant p.(R88*) in seven patients representing 32% of VTE cases. Additionally, we report one novel variant c.356G > T, p.(G119V) in the F7 gene, considered to be pathogenic in this study.

CONCLUSIONS

Our studies finding illustrates the ability of targeted next-generation sequencing to uncover uncommon/unknown genetic variants that may predispose to thrombophilia. The finding of the novel variant in the F7 gene extends the spectrum of variants affecting thrombosis. While a comparatively small number of subjects have been included in our cohort, the findings summarize the possible genetic features of thrombophilia.

The Spectrum of Mutations of Homocystinuria in the MENA Region

Homocystinuria is an inborn error of metabolism due to the deficiency in cystathionine beta-synthase (CBS) enzyme activity. It leads to the elevation of both homocysteine and methionine levels in the blood and urine. Consequently, this build-up could lead to several complications such as nearsightedness, dislocated eye lenses, a variety of psychiatric and behavioral disorders, as well as vascular system complications. The prevalence of homocystinuria is around 1/200,000 births worldwide. However, its prevalence in the Gulf region, notably Qatar, is exceptionally high and reached 1:1800. To date, more than 191 pathogenic CBS mutations have been documented. The majority of these mutations were identified in Caucasians of European ancestry, whereas only a few mutations from African-Americans or Asians were reported. Approximately 87% of all CBS mutations are missense and do not target the CBS catalytic site, but rather result in unstable misfolded proteins lacking the normal biological function, designating them for degradation. The early detection of homocystinuria along with low protein and methionine-restricted diet is the best treatment approach for all types of homocystinuria patients. Yet, less than 50% of affected individuals show a significant reduction in plasma homocysteine levels after treatment. Patients who fail to lower the elevated homocysteine levels, through high protein-restricted diet or by B6 and folic acid supplements, are at higher risk for cardiovascular diseases, neurodegenerative diseases, neural tube defects, and other severe clinical complications. This review aims to examine the mutations spectrum of the CBS gene, the disease management, as well as the current and potential treatment approaches with a greater emphasis on studies reported in the Middle East and North Africa (MENA) region.

Triple thrombophilic simultaneous mutations in patients after bariatric surgery: is there a role for screening in the Eastern Mediterranean?

Background and purpose: Thrombophilia is a hypercoagulable state that predisposes to thrombosis. Several genetic risk factors have been shown to predispose to thromboembolic events. Homozygosity to a thrombophilic mutation certainly predisposes the affected patient to more serious symptoms. Materials and methods: Here we present a case of a 56-year-old male patient who underwent sleeve gastrectomy for morbid obesity, presenting to our institution with abdominal pain. Investigations revealed thrombosis of the splenic, axillary vein as well as the right pulmonary artery. The patient was found to have triple thrombophilic mutations. Results: To our knowledge, this is the first reported case of three specific simultaneous thrombophilic mutations in a patient from the Eastern Middle East. Conclusion: We suggest a role for screening for thrombophilic mutations in the Eastern Mediterranean patients undergoing bariatric surgeries for morbid obesity due to the increased risk of thrombosis in this group of patients

Epidemiology of activated protein C resistance and factor v leiden mutation in the mediterranean region

Venous thromboembolic disorders (VTE) are serious disorders with high morbidity and mortality rates. Many genetic and acquired risk factors were identified to cause VTE. The most common genetic risk factor is Factor V Leiden mutation (FVL). FVL was found in high percentage of populations of Caucasian origin but was almost absent in non-Caucasians. It was also reported in populations living in North Africa and the Middle East. This review article briefly explains FVL and how it causes VTE, the distribution of FVL worldwide, and then it elaborates on the epidemiology of FVL in the Mediterranean Region and how this brought speculations that FVL might have originated in the Eastern Mediterranean area.

Race differences in the prevalence of the factor V Leiden mutation in Kuwaiti nationals

Factor V Leiden mutation (FVL; G1691A) is an established risk factor for venous thromboembolic disorders. FVL was reported with high prevalence in Caucasians (1-15%) but was absent in non-Caucasians like Africans and Asians. Studies reported FVL in 5-27% of Arabs and non-Arabs living in the Middle Eastern countries northern to the Arabian Peninsula, but was almost absent in Arabs in the Arabian Peninsula itself. Kuwait is an Arabic country present on the northern border of the Arabian Peninsula, and Kuwaitis are originally from Saudi Arabia (Southern to Kuwait and within the Arabian Peninsula) or from Iran and Iraq (northern to Kuwait and the Arabian Peninsula). This study was conducted to study FVL in Kuwaitis in relation to their origin. Real-time PCR was performed on DNA samples of 285 apparently healthy Kuwaitis using specially designed primers and probes for FVL. There were 109 Kuwaitis of Iranian origin, 71 of Iraqi origin and 105 of Saudi origin. FVL was present in 7 and 5 Kuwaitis of Iranian and Iraqi origin, respectively. None of the Kuwaitis of Saudi origin had the mutation. Prevalence of FVL in Kuwaitis of Iranian (6.42%) and Iraqi (7.04%) origin were statistically different from prevalence in Kuwaitis of Saudi (0%) origin (P-value<0.05). No difference was found between females and males (P-value>0.6). In conclusion, FVL is present in Kuwaitis of Iranian or Iraqi origin only. Therefore, testing and providing genetic consultation for FVL may be needed in those Kuwaitis only which should save time, cost and efforts. However, this assumption should be confirmed by other studies and on larger number of cases.

Association between apolipoprotein ε4 allele, factor V Leiden, and plasma lipid and lipoprotein levels with sickle cell disease in Southern Iran

To investigate whether there is any association between various APOE alleles and factor V Leiden (FVL) with lipid profiles and sickle cell disease (SCD) in Southern Iran. 65 SCD patients consisting of 35 sickle cell anemia homozygous (SS), 15 sickle cell heterozygous (AS) and 15 sickle cell/βThalassemia (S/βthal) patients and 68 healthy individuals with normal hematological indices were studied. APOE and FVL polymorphisms were detected by PCR-RFLP and serum lipid level was measured enzymatically. The frequencies of FVL and APOE-ε4 allele were significantly higher in SCD patients than in control (15.4 vs. 4.4 and 13.7% vs. 3.3%, respectively). The distributions of APOE ε3ε3, ε2ε3 and ε2ε4 + ε3ε4 alleles in SCD patients were significantly different from those in the control group. The SCD subjects particularly SS/S βthal (SS + S/βthal) and SS patients have significantly lower frequency of APOE ε3ε3 allele (P < 0.05) whereas SCD, SS patients and AS individuals have a significantly higher frequency of APOE ε4 allele (ε2ε4 + ε3ε4; P = 0.003, P = 0.011 and P = 0.035, respectively) compared to the control group. The LDL-C (P = 0.006) and total cholesterol (P < 0.001) levels in SCD subjects were found to be significantly lower than those in the control group. In addition, the presence of non-APOE ε4 allele (ε2ε3 + ε3ε3) resulted in a significant decrease in the level of LDL-C and total cholesterol in SCD subjects in general and in SS and SS/S βthal patients in particular compared to controls. Furthermore, the presence of APOE ε4 allele (ε2ε4 + ε3ε4) was found to be associated with the risk of sickle cell anemia [OR = 4.1, P = 0.04]. The presence of either FVL mutation (OR = 4.6; CI: 0.91-24, P = 0.07) or APOE-ε4 allele (OR = 4.07; CI: 1.01-16.4, P = 0.048) is associated with the risk of sickle cell disease in Southern Iran. This data suggest that the activation of coagulation system enhances thrombus generation and decreases antioxidant activity in SCD patients from Southern Iran.