Homozygous Methylenetetrahydrofolate Reductase Research Articles

Bilateral multiple recurrent branch retinal vein occlusions secondary to hypercoagulopathy associated with multiple mutations: A rare case report

Abstract: Retinal vein occlusions (RVOs) are relatively common vascular disorders, often resulting in significant visual impairment. We present an intriguing case of a 53-year-old male with recurrent bilateral branch RVOs stemming from underlying hypercoagulopathy. This complex scenario encompassed simultaneous bilateral RVO occurrences and subsequent unilateral recurrences. Despite the absence of systemic comorbidities or conventional risk factors, genetic assessment unveiled notable heterozygous mutations involving Factor V Leiden (G1691A) and Factor II (PT G20210A), along with a homozygous methylenetetrahydrofolate reductase A1298C mutation. While routine hematological indicators remained largely unremarkable, the marked efficacy of anti-vascular endothelial growth factor (anti-VEGF) agents, particularly when administered promptly, emerged as a noteworthy therapeutic avenue. This case underscores the imperative of scrutinizing thrombotic mutations in youthful patients with recurrent RVOs, accentuating the favorable retinal response to anti-VEGF interventions and emphasizing the rewards of timely clinical intervention.

Homozygous MTHFR C677T carriers develop idiopathic portal vein thrombosis 20 years earlier than wild type.

The aim of this study was to evaluate the impact of methylene tetrahydrofolate reductase (MTHFR) rs1801133 (C→T667 transition) on age at first idiopathic portal vein thrombosis (PVT) and to identify clinical and/or laboratory variables influencing age at first PVT, including plasma homocysteine and the prothrombin rs1799963 PT (G→A transition at position 20210) (PT) mutation. A retrospective cross-sectional cohort, including 15 MTHFR TT, 32 MTHFR TC and 22 MTHFR CC idiopathic PVT participants contributing demographics, age at PVT, plasma concentrations of homocysteine and of natural anticoagulants. MTHFR TT carriers presented with a lower age at PVT than heterozygous or wild-type genotypes (31 ± 8 vs. 48 ± 15 vs. 52 ± 13 years, P = 0.001) and were more likely to have a plasma HC concentration above the cut-off (73.3 vs. 32 vs. 50%, P = 0.04). MTHFR TT and protein C predicted age at PVT ( P < 0.0001 and P = 0.06); MTHFR TT predicted plasma homocysteine ( P = 0.05). In the MTHFR TT group, plasma homocysteine inversely related to protein C ( P = 0.03). Plasma homocysteine predicted the extent of PVT ( P = 0.03). Compound MTHFR TT + PT GA did not lower age at first PVT compared to MTHFR TT alone (35 ± 9 vs. 30 ± 8 years). MTHFR TT is associated with a 20-year earlier PVT presentation than heterozygous and wild-type MTHFR genotypes. The inverse relation between plasma homocysteine and protein C contributes to the prematurity of PVT in the MTHFR TT group, whereas plasma homocysteine contributes to the extent of PVT. The recent exclusion of MTHFR genotyping from the thrombophilia screen needs revisiting in this setting.

Inherited thrombophilia gene mutations and risk of venous thromboembolism in patients with cancer: A systematic review and meta-analysis.

In the general population, individuals with an inherited thrombophilia have a higher risk of thrombosis, but the effect of inherited thrombophilia on the risk of cancer-associated venous thromboembolism (VTE) remains controversial. Our objective was to determine the risk of VTE in cancer patients with inherited thrombophilia. We conducted a systematic review and meta-analysis of studies reporting on VTE after a cancer diagnosis in adult patients who were tested for inherited thrombophilia. In September 2022, we searched Medline, EMBASE, and Cochrane Central. Two reviewers screened the abstracts/full texts and assessed study quality using the Quality in Prognostic Studies tool. We used Mantel-Haenszel random-effects models to estimate pooled odds ratios (OR) of VTE and 95% confidence intervals (95%CI). We included 37 and 28 studies in the systematic review and meta-analysis, respectively. Most studies focused on specific cancer types and hematologic malignancies were rare. The risk of VTE was significantly higher in cancer patients with non-O (compared with O) blood types (OR: 1.56 [95% CI: 1.28-1.90]), Factor V Leiden, and Prothrombin Factor II G20210A mutations compared with wild types (OR: 2.28 [95% CI: 1.51-3.48] and 2.14 [95% CI: 1.14-4.03], respectively). Additionally, heterozygous and homozygous methylenetetrahydrofolate reductase C677T had ORs of 1.50 (95% CI: 1.00-2.24) and 1.38 (95% CI: 0.87-2.22), respectively. Among those with Plasminogen-Activator Inhibitor-1 4G/5G, Vascular Endothelial Growth Factor (VEGF) A C634G, and VEGF C2578A mutations, there was no significant association with VTE. In conclusion, this meta-analysis provided evidence that non-O blood types, Factor V Leiden, and Prothrombin Factor II G20210A mutations are important genetic risk factors for VTE in cancer patients.

Ischaemic stroke with multi-focal venous and arterial thrombosis due to hyperhomocysteinemia: anabolic androgenic steroid use and MTHFR c.667 C > T variant – a case report

BackgroundSeverely elevated serum homocysteine is a rare cause of ischaemic stroke and extra-cranial arterial and venous thrombosis. Several factors can lead to mild elevation of homocysteine including dietary folate and B12 deficiency, and genetic variants of the methylenetetrahydrofolate reductase (MTHFR) enzyme. The use of Anabolic androgenic steroid (AAS) is under-reported, but increasingly linked to ischaemic stroke and can raise homocysteine levels.Case ReportWe present a case of a man in his 40s with a large left middle cerebral artery (MCA) territory ischaemic stroke and combined multifocal, extracranial venous, and arterial thrombosis. His past medical history was significant for Crohn’s disease and covert use of AAS. A young stroke screen was negative except for a severely elevated total homocysteine concentration, folate and B12 deficiencies. Further tests revealed he was homozygous for the methylenetetrahydrofolate reductase enzyme thermolabile variant (MTHFR c.667 C > T). The etiology of this stroke was a hypercoagulable state induced by raised plasma homocysteine. Raised homocysteine in this case was likely multifactorial and related to chronic AAS use in combination with the homozygous MTHFR c.677 C > T thermolabile variant, folate deficiency and, vitamin B12 deficiency.ConclusionIn summary, hyperhomocysteinemia is an important potential cause of ischaemic stroke and may result from genetic, dietary, and social factors. Anabolic androgenic steroid use is an important risk factor for clinicians to consider, particularly in cases of young stroke with elevated serum homocysteine. Testing for MFTHR variants in stroke patients with raised homocysteine may be useful to guide secondary stroke prevention through adequate vitamin supplementation. Further studies looking into primary and secondary stroke prevention in the high-risk MTHFR variant cohort are necessary.

Reduced Steroid Synthesis in the Follicular Fluid of MTHFR 677TT Mutation Carriers: Effects of Increased Folic Acid Administration.

Objective To compare steroid profiles in the follicular fluid (FF) from women homozygous for the methylenetetrahydrofolate reductase (MTHFR) 677C>T mutation and wildtype controls and to correlate it with the folic acid administration scheme applied at the time of oocyte retrieval. Design Retrospective single center study. Subjects and Methods Infertile patients treated by using assisted reproductive techniques were genotyped routinely for the MTHFR 677C>T mutation. In 2006 they had received folic acid supplementation doses of 400 µg daily per os. This group was designated Group-400 (n = 10). From 2008 onwards, all of our infertility patients received a daily dose of 800 µg folic acid per os. Women from this group were designated Group-800 (n = 28). FF were collected and a panel of steroid hormones (estradiol, estrone, estriol, cortisol, progesterone, 17-OH progesterone, testosterone, androstenedione, aldosterone, DHEA, and DHEA-S) was measured by isotope dilution liquid chromatography-tandem mass spectrometry employing atmospheric pressure photo ionization (APPI). Results In Group-400, the FF hormone profile confirmed a significant reduction of estradiol in homozygous 677TT carriers (0.52 ± 0.08-fold, exact p = 0.032) and for the first time also revealed significantly reduced estriol concentrations in these individuals (0.54 ± 0.05-fold, p = 0.016), as compared to wildtype controls. In Group-800, no significant differences were found for concentrations of any of the steroid hormones between homozygous 677TT carriers and wildtype controls. Conclusions The current findings support and extend previous reports on reduced concentrations of specific steroid hormones in follicular fluids of homozygous MTHFR 677C>T mutation carriers. The restoration of the FF hormone profile by elevated-dose folic acid supplementation might impact performing ART in infertile women with the MTHFR 677TT-genotype. Further adequately powered studies are necessary to verify our finding and to demonstrate the clinical effect of enhanced folic supplementation on ovarian function.

Hepatic Vein Thrombosis in a COVID-19 Patient with Hereditary Thrombophilia: A Case Report

Background: COVID-19 is an infection secondary to the novel SARS-COV-2 virus with a well-established increased risk for thrombotic events. However, the interaction between COVID-19 and other patient-specific hereditary or acquired thrombophilias remains a poorly explored area. Case Presentation: We herein report a case of a 23-year-old Caucasian female with known risk factors for coagulopathy (smoking, oral contraceptives, anti-phospholipid (aPL) antibodies, heterozygous Factor V Leiden mutation, and homozygous methylenetetrahydrofolate reductase (MTHFR) mutation) who developed a Budd-Chiari syndrome after testing positive for COVID-19. To our knowledge, this is the first report of a case of splanchnic vein thrombosis in a COVID-19 patient with the above risk factors. Conclusion: Such a presentation underscores the additional increased thrombotic risk attributed to COVID-19 infections in the setting of underlying hereditary or acquired thrombophilias.

Juvenile patients with the homozygous MTHFR C677T genotype develop ischemic stroke 5 years earlier than wild type.

To compare age at 1st ischaemic stroke (IS) in a cohort of juvenile (< 46years of age) IS patients evaluated for the rs1801133 polymorphism (C → T677) of the methylene tetrahydrofolate reductase (MTHFR) gene; to identify predictors of age at IS and of type of cerebral vessel involvement, small vessel disease (SVD) vs large vessel disease (LVD) responsible for the IS; to evaluate possible associations between other clinical and laboratory variables. Retrospective cohort study on 82 MTHFR TT, 54 MTHFR TC and 34 MTHFR CC participants; data regarding age, sex, age at IS, history of dyslipidaemia, hypertension, smoking, migraine and homocysteine (HC) as well as neuroimaging were collected. Age at IS was lower in MTHFR TT than MTHFR TC and CC (35 ± 4 vs 38 ± 0 vs 40 ± 3years, respectively, p = 0.002); plasma HC(median, interquartile range) was higher in MTHFR TT than in the other groups [16.7 (11.8, 28.6) vs 11.4 (8.2, 16.1) vs 9.8 (7.9, 1.3) respectively, p < 0.0001)] and was higher in SVD than LVD[17.4 (12.4, 32.5) vs 11.4 (8.8, 16.4) p < 0.0001]. MTHFR TT independently predicted age at IS (p = 0.0008) alongside smoking both as a categorical (p = 0.003) or continuous variable (p = 0.02), whereas HC independently predicted SVD as categorical (p = 0.01) and continuous variable (p < 0.0001). Smoking positively predicted plasma HC (p = 0.005) and negatively the activated partial thromboplastin ratio (aPTTr) (p = 0.02). Juvenile IS carriers of the MTHFR TT genotype develop their 1st occlusion on average 5years earlier compared to the CC genotype; smoking contributes to this prematurity adversely affecting plasma HC and coagulation whereas plasma HC predicts IS secondary to SVD. Public health campaigns against smoking should highlight the prematurity of IS in the juvenile population.

P1682: MTHFR C677T GENOTYPE IN CORRELATION WITH THROMBOSIS AND ASSOCIATION WITH FVIII COAGULANT ACTIVITY IN GREEK PAEDIATRIC POPULATION

Background: The polymorphism C>T substitution in position 677 (C677T) of the encoding gene of methylenetetrahydrofolate reductase (MTHFR), creates a thermolabile enzyme with reduced activity that may predispose to hyperhomocysteinemia, an established risk factor for arterial thrombosis and premature atherosclerosis and a probable risk factor for venous thromboembolic disease and its recurrence in the general population. There are conflicting results as to the role of the MTHFR C677T polymorphism as a risk factor for thrombosis. Although the homozygous substitution is often associated with hyperhomocysteinemia, mainly in folate deficiency, a clear association between this genetic marker and thrombosis has not yet been established. Aims: Primary aim was to evaluate the prevalence of mutant C677T MTHFR and its association with thrombosis in the Greek paediatric population. Secondary aim was to evaluate whether different MTHFR genotype is associated with evidence of activation of coagulation cascade through increased factor VIII activity. Methods: Data were retrospectively collected from children referred to our Haemostasis and Thrombosis Centre for laboratory screening of thrombophilia between 2018 and 2020. Some of them were checked due to history of thrombosis. Children were categorized according to MTHFR C677T genotype. FVIII Coagulant activity (%) was measured by One Stage Assay, away from acute thrombosis. The identification of mutations was based on polymerase chain reaction (PCR) and reverse- hybridization. Statistical analysis was performed with t-test and ANOVA. Results: A total of 688 children (boys: 49 %) of mean age 8.9± 8 years (0-18) were investigated. Twelve percent (81/688) of them had history of thrombosis, mainly venous thromboembolic disease. Children were categorized as follows: homozygous MTHFR C677T (15%), heterozygous (47%) and normal (38%). There was thrombosis history in 12% of homozygous MTHFR C677T, 11% heterozygous and 12 % of normal, fact showing that there is no association between MTHFR C677T genotype with thrombosis. Children with homozygosity MTHFR C677T, compared to children with heterozygosity and normal MTHFR C677T showed increased factor VIII values (132.8 vs 126.4 and 131.6, %, respectively), but without statistically significant difference. However, independently of MTHFR C677T genotype, mean factor VIII values were significantly increased in all children, with thrombosis history when they were compared to children without thrombosis history (161.3 vs 125.1, %, p<0.001). Interestingly, in children with thrombosis, mean factor VIII level was statistically increased in heterozygous and normal MTHFR C677T in contrast to children with MTHFR C677T homozygosity, in whom no statistically significant increase was found (166.9 vs 121.4, %-p<0.05, 160.2 vs 127.6, %-p<0.05 and 148.3 vs 130.6, %-p>0.05, respectively). Finally, it should be noticed that during the year 2020 mean factor VIII values were much increased in all children in comparison to the years 2018, 2019 and 2021 (137 vs 129, 123 and 127, %, respectively), probably reflecting the effects of unknown pandemic COVID-19 which initiated in 2020, and showing that factor VIII could be an evidence of stress condition. Summary/Conclusion: There is no probably association between MTHFR C677T genotype and thrombosis in our paediatric population. Moreover, it was not proved that different MTHFR genotypes affect factor VIII activity.

Earlier onset of peripheral arterial thrombosis in homozygous MTHFR C677T carriers than in other MTHFR genotypes: a cohort study.

To investigate whether age at first presentation of pure peripheral arterial thrombosis (PAT) in lower and upper limbs and in the splanchnic circulation occurs earlier in carriers of the methylenetetrahydrofolate reductase (MTHFR) T677T genotype compared to the heterozygous and wild type and to identify predictors of a possible earlier onset. Retrospective cohort study on 27 MTHFR TT, 29 MTHFR TC and 29 MTHFR CC participants; data regarding age, sex, age at PAT, clinical history (dyslipidaemia, hypertension, smoking, obesity) and homocysteine (HC) measured by immunoassay were collected. Age at PAT was lower in MTHFR TT than MTHFR TC and CC (43 ± 9 vs 47 ± 9 vs 51 ± 4years, respectively, p = 0.02); plasma HC was higher in MTHFR TT than in the other groups (25 ± 19 vs 12.7 ± 6.7 vs 11.3 ± 3.3μmol/l, respectively, p < 0.001) while the activated partial thromboplastin ratio (aPTTr) was lower in MTHFR TT than in other genotypes (0.90 ± 0.10 vs 0.97 ± 0.12 vs 0.97 ± 0.08μmol/L p < 0.001). Among categorical variables, MTHFR TT and dyslipidaemia independently predicted age at AT (p = 0.01 & p = 0.03, respectively) whereas among the continuous variables HC independently predicted age at PAT (p = 0.02) as well as the aPTTr (p = 0.001); smoking predicted lower limb PAT (p = 0.005). MTHFR TT carriers develop their first PAT an average of 4 and 8years earlier than MTHF CT and CC genotypes; MTHFR TT, dyslipidaemia and plasma HC contribute to the prematurity of the PAT while the interplay between elevated HC and smoking may affect type of arterial district occlusion.

A Case of Budd-Chiari Syndrome Associated with Erythrocytosis and Homozygous MTHFR C677T Mutation

An erythrocytosis describes an increased erythrocyte, subclassified into relative due to hemoconcentration or absolute by an increase in erythrocyte mass, defined as an increase in hemoglobin concentration and/or hematocrit in the peripheral blood above the sex-specific normal range. Budd-Chiari Syndrome (BCS) is related to an obstruction of the hepatic venous flow leading to occlusion of hepatic veins and their tributaries. Genetic and environmental factors can interact for risk determination of venous thromboembolism. The risk associated with SNP 677C&gt;T and 1298A&gt;C of the methylenetetrahydrofolate reductase (MTHFR), 1691G&gt;A of the Factor V Leiden (FVL) and 20210G&gt;A of the prothrombin (FII) genes were investigated in many studies involving thrombosis. This case report describes the clinical, hematological and biochemistry data about a 48-year-old woman diagnosed with PV and a BCS associated, also carrying 677C&gt;T SNP in homozygosity. The patient started therapy with phlebotomy, hydroxyurea and oral anticoagulant. Currently, she presents a better clinical and laboratory condition with normalized values of hematological and platelet indices. This case report aims to contribute with evidence of related comorbidities and makes it possible to report that genetic factors are involved since the patient's mother had already been diagnosed with absolute erythrocytosis in 2016 at 78 years old. For this main result, we understand that it is clear that a family genetic study can reveal clinical modifying factors in these patients, as there are different clinical severities in the family. Furthermore, we believe in the need for a greater number of randomized clinical trials to add better evidence to complement an ideal therapeutic approach in these patients.

Association of thrombophilia prospective detection with hemocompatibility related outcomes in left ventricular assist device patients.

Inherited thrombophilias represent a concerning risk factor due to a proclivity to an aberrant clot formation. However, in patients with left ventricular assist device (LVAD), their impact on bleeding and thrombotic complications remains still poorly understood. The aim of the present study was to evaluate the effect of thrombophilic mutation directed anticoagulation therapy on adverse clinical outcomes in LVAD patients. About 138 consecutive patients indicated for LVAD implant (HeartMate II, Abbott, Plymouth, USA) were prospectively screened for three major thrombophilic mutations: factor II (prothrombin), factor V Leiden, and homozygous methylenetetrahydrofolate reductase (MTHFR). Subsequently, discordant individualized anticoagulation targets of INR 2.5-3.0 in thrombophilia positive and INR 1.8-2.2 in negative patients were established; notably without anti-platelet agents given the center standard of care. Mean age was 50 ± 12.7 years, 83% male. Mean duration of support was 464.5 days (SD 482.9; SEM 41.1) and median of 310 days (IQR 162; 546). Full thrombophilia positive cohort analysis has not revealed any significant impact on event free survival. In contrast, detailed analysis of specific thrombophilias subsets has revealed Factor II prothrombin mutation as a significant predisposition for the pump thrombosis risk (SHR 10.48; p = 0.001) despite more aggressive prespecified anticoagulation target. Moreover, the incidence of bleeding events in prothrombin group was also significantly increased (SHR 6.0; p = 0.03). Our observations suggest that specific thrombophilias in LVAD patients may pose different intensity predisposition for thrombotic complications. Factor II (prothrombin) positive mutation was identified as significant risk factor associated with the pump thrombosis.

Combined Effect of MTHFR C677T and PAI-1 4G/5G Polymorphisms on the Risk of Venous Thromboembolism in Chinese Lung Cancer Patients.

Venous thromboembolism (VTE) is a common and potentially fatal complication in cancer patients. Although several genetic risk factors related to thrombophilia have been identified, their contributions for the occurrence of VTE in cancer patients have conflicting results. The aim of this study was to evaluated the gene polymorphisms of methylenetetrahydrofolate reductase (MTHFR) C677T and plasminogen activator inhibitor-1 (PAI-1) 4G/5G in lung cancer patients, with and without VTE, and the combined effect on the risk of VTE. 92 lung cancer patients diagnosed with VTE (VTE group) and 122 lung cancer patients without VTE (non-VTE group) were enrolled in the study. The gene polymorphisms were analyzed by the method of polymerase chain reaction-restriction fragment length polymorphism. Gene mutation of factor V Leiden was not detected both in non-VTE group and VTE group. The frequency of MTHFR C677T homozygous mutation in VTE group was 25.00%, higher than that in the non-VTE group without statistical difference. It was found that the PAI-1 4G4G genotype is associated with a higher risk of VTE (OR: 2.62, 95%CI: 1.19-5.75). Interestingly, the interaction between MTHFR C677T and PAI-1 4G/5G polymorphisms showed that the coexistence of the 2 homozygous mutation could further increase the risk of VTE. In conclusion, PAI-1 4G/5G polymorphism may be an increased risk factor for VTE among lung cancer patients in Chinese population. The homozygous MTHFR C677T mutation may be not a risk factor for VTE but increases the risk, accompanied with PAI-1 4G5G genotype.

S2107 Successful Management of Refractory Esophageal Variceal Bleeding Secondary to Chronic Portal Vein Thrombosis by Transsplenic Portal Vein Recanalization and Transjugular Intrahepatic Portosystemic Shunt

INTRODUCTION: Trans-jugular intrahepatic portosystemic shunt (TIPS) becomes challenging in the presence of portal vein thrombus (PVT). We describe a case of successful management of refractory esophageal variceal bleeding secondary to chronic PVT and splenic vein thrombosis (SVT) by portal vein recanalization – TIPS through transsplenic and transhepatic approach. CASE DESCRIPTION/METHODS: A 29-year-old male with a history of homozygous methylenetetrahydrofolate reductase mutation with normal homocysteine levels on warfarin presented with acute hematemesis. He underwent emergent endoscopic band ligation of esophageal and GOV1 gastric varices. He had a history of chronic PVT with prior mechanical thrombectomy and thrombolysis two years ago, and received band ligation for bleeding esophageal varices in the last year, but did not follow up for surveillance. MRI of abdomen and pelvis revealed chronic PVT with cavernous transformation (Fig A) and chronic SVT. No further bleeding was reported after endoscopy. Liver biopsy one year ago showed benign liver tissue with focal mild congestion and sinusoidal dilation. There was a normal hepatic venous pressure gradient. Given concerns about his compliance and risk of re-bleeding, multidisciplinary team discussion led to consideration of a high-risk TIPS with splenic vein recanalization and stenting. Under ultrasound and fluoroscopic guidance, TIPS was placed using two snare targets. One snare was placed in the occluded portal vein via splenic vein access, and another was placed in the middle hepatic vein via internal jugular vein access. Using the gun-sight technique, a 21-gauge Chiba needle was advanced transhepatically through both the loop snares and then a guidewire was advanced until it could be captured by both the above snares (Fig B). With this newly obtained access, TIPS and splenic stents were successfully deployed (Fig C). Pressure gradient across TIPS was lowered to 6 mm Hg from 16 mm Hg. As varices did not fill on post TIPS portogram, embolization was not performed. He was started on aspirin in addition to his warfarin. Repeat CTA at 3 months demonstrated patent TIPS and splenic stent, and no further episodes of hematemesis were reported. DISCUSSION: In our patient, the gunsight TIPS approach helped decompress portal hypertension and prevent recurrent variceal bleeding when other alternatives including Sugiura surgery carried high morbidity and were not amenable. Post TIPS re-stenosis is a known complication, and may be prevented by aspirin and warfarin use.Figure 1.: Magnetic resonance imaging (MRI) of the abdomen and pelvis showing chronic portal vein thrombosis with cavernous transformation.Figure 2.: Fluoroscopic image showing gun-sight technique: Guide-wire is captured by the first snare in the presumed right portal vein and second snare in the middle hepatic vein.Figure 3.: Fluoroscopic image showing successful deployment of TIPS.

Case Report: Homozygous C677T MTHFR Gene Mutation in Male with Hypogonadism

We report a 44-year-old male, who was diagnosed with hypogonadotropic hypogonadism after complaining of erectile dysfunction, depression, and fatigue. He was started on testosterone replacement therapy. He persistently complained of fatigue despite increasing the dose of testosterone over two years and having therapeutic testosterone levels. He was found to have homozygous C677T methylenetetrahydrofolate reductase (MTHFR) gene mutation. After treatment with folate and B12, his symptoms resolve completely. MTHFR is a key enzyme in the folate pathway, and it plays an essential role in homocysteine metabolism. Homozygous C677T individuals have decreased activity of MTHFR enzyme with increased homocysteine levels, which is associated with increased risk of thrombosis. An association has been reported between C677T variant and male infertility. Patients identified to have hyperhomocysteinemia should be treated with B-complex vitamin supplements. Our case emphasizes other possible etiologies for fatigue and erectile dysfunction in a male with hypogonadism on testosterone therapy. Also, it shows possible association between MTHFR gene mutation and male hypogonadism.

SAT-LB68 A Rare De Novo Mutation in LRP5 Gene in an Adolescent Female With Juvenile Onset Primary Osteoporosis

Background: Juvenile onset of primary osteoporosis is a rare skeletal disorder with a highly heterogenous clinical presentation and complex poorly understood genetic etiology. Low-density lipoprotein receptor-related protein 5 (LRP5), a Wnt-β-catenin pathway receptor involved in bone mineral density (BMD) regulation, has been reported in children with primary osteoporosis mainly due to missense and frame-shift mutations. To our knowledge, there is only one report of in-frame deletions in exon 21 possibly being implicated in pregnancy related osteoporosis (1). We report the first case of a rare heterozygous de novo in-frame deletion in exon 21 of LRP5 gene in a girl with juvenile onset primary osteoporosis. Clinical Case: A 7.5 yo previously healthy European-African-American female born to non-consanguineous family, was noted to have left ankle and bilateral wrists fractures during sport activities occurring over the span of 1 y. On exam, she was of normal stature, had normal sclerae and vision, but was found to have hypermobile joints. Initial blood work revealed an elevated iPTH 72 pg/mL (9-59), normal Ca 9.6 mg/dL (8.9-10.4), and low 25OH-Vitamin D 17 ng/mL (30-100), which normalized with supplementation to 30.4 ng/mL. By 10.5 yo, she had sustained multiple sports related and pathologic fractures of long bones with progressive bone pain and functional ambulatory impairment. Radiographic evaluation showed osteopenia, multiple healed long bone fractures with presumed non-ossifying fibroma in the distal right femoral metaphysis, and subtle height loss of T4-5 vertebrae. CT bone densitometry at 12 yo showed low mean cancellous lumbar vertebral BMD of 190 mg/cm3 (ref. 285 ± 45) and normal cortical BMD of the femoral midshaft of 1977 mg/cm3 (ref. 2000 ± 60). Genetic testing for Osteogenesis Imperfecta returned negative for COL1A1 and COL1A2 mutations. Whole exome sequencing (WES) revealed a rare, de novo heterozygous mutation in exon 21 that involved deletion of nucleotides 4454 to 4465 resulting in an in-frame deletion of amino acid 1485 to 1488. This mutation is predicted to be deleterious by in silico analysis. Conclusion: We present the first case of a young female with progressive pathologic fractures, functional ambulatory impairment, and low BMD in childhood, consistent with juvenile onset primary osteoporosis. WES revealed a rare de novo heterozygous in-frame deletion mutation in LRP5, providing a plausible biological mechanism for her clinical presentation, and further contributing to the increasing genetic heterogeneity of juvenile onset primary osteoporosis and LRP5-related bone disorders. Reference: (1) Cook, F., Mumm, S., Whyte, M., Wenkert, D. Pregnancy-associated osteoporosis with a heterozygous deactivating LDL receptor-related protein 5 (LRP5) mutation and a homozygous methylenetetrahydrofolate reductase (MTHRF) polymorphism. JBMR. 2014;29 (4): 922-8.

5-Fluorouracil degradation rate as a predictive biomarker of toxicity in breast cancer patients treated with capecitabine

Capecitabine is an oral prodrug of 5-fluorouracil with a relevant role in the treatment of breast cancer. Severe and unexpected toxicities related to capecitabine are not rare, and the identification of biomarkers is challenging. We evaluate the relationship between dihydropyrimidine dehydrogenase, thymidylate synthase enhancer region and methylenetetrahydrofolate reductase polymorphisms, 5-fluorouracil degradation rate and the onset of G3-4 toxicities in breast cancer patients. Genetic polymorphisms and the 5-fluorouracil degradation rate of breast cancer patients treated with capecitabine were retrospectively studied. Genetic markers and the 5-fluorouracil degradation rate were correlated with the reported toxicities. Thirty-seven patients with a median age of 58 years old treated with capecitabine for stages II-IV breast cancer were included in this study. Overall, 34 (91.9%) patients suffered from at least an episode of any grade toxicity while nine patients had G3-4 toxicity. Homozygous methylenetetrahydrofolate reductase 677TT was found to be significantly related to haematological toxicity (OR = 6.5 [95% IC 1.1-37.5], P = 0.04). Three patients had a degradation rate less than 0.86 ng/mL/106 cells/min and three patients greater than 2.1 ng/mL/106 cells/min. At a univariate logistic regression analysis, an altered value of 5-fluorouracil degradation rate (values < 0.86 or >2.10 ng/mL/106 cells/min) increased the risk of G3-4 adverse events (OR = 10.40 [95% IC: 1.48-7.99], P = 0.02). A multivariate logistic regression analysis, adjusted for age, comorbidity and CAPE-regimen, confirmed the role of 5-fluorouracil degradation rate as a predictor of G3-4 toxicity occurrence (OR = 10.9 [95% IC 1.2-96.2], P = 0.03). The pre-treatment evaluation of 5-fluorouracil degradation rate allows to identify breast cancer patients at high risk for severe 5-FU toxicity.

Inherited prothrombotic risk factors in children with hereditary angioedema

Aim: Hereditary angioedema is characterized with recurrent mucocutaneous angioedema, abdominal pain, edema of larynx and extremities. Dermal vascular thrombosis and systemic coagulation may occur in patients with hereditary angioedema due to inhibition of activated factor XII, thrombin and plasmin. Aim of this study was to screen patients with HAE for prothrombotic genetic risk factors before treatment.Material and Methods: Ten patients with hereditary angioedema who were followed up at our clinic were included in our study. The type and frequency of attack, use of prophylaxis and family history of hereditary angioedema were questioned and prothrombotic risk factors were studied.Results: Among the 10 included patients, five of them were male (50%) and five were female (50%). Four patients had abdominal edema (40%), four patients had edema of hands, feet and face (40%). One patient (10%) had heterozygous factor V G1691A mutation, another one had also heterozygous protrombin G20210A mutation. The heterozygous methylene tetrahydrofolate reductase (MTHFR) mutation were identified in seven patients (70%) and homozygous MTHFR mutation were found two patients (20%).Conclusion: In patients with hereditary angioedema, evaluation of protrombotic risk factors was crucial to estimate attack frequency-severity and treatment related thrombosis risk.Keywords: Hereditary angioedema; prothrombotic risk factors; C1 inhibitor; thrombosis.

Complex Nature of Neural Tube Defects: A Regional Experience

Objective: The underlying gene-environment interaction of fetal neural tube defects is affected by several factors including geography, ethnicity and time. Local features of fetal neural tube defects were described.Study Design: A prospective cohort study of 48 fetal neural tube defects in a single tertiary medical center at the northwestern region of Turkey (2013-2015) was done via ultrasound, magnetic resonance imaging (MRI), conventional karyotyping, maternal methylenetetrahydrofolate reductase c.677C&gt;T (rs1801133) single-nucleotide polymorphism and maternal serum levels of folic acid, vitamin B12 and zinc. For comparison of means, a Student’s T-Test was used.Results: The prevalence of neural tube defects was 11.4 per 10000 births (48/42000) in northwestern Turkey. The defects on the cranium (n=23; 47.9%) and spine (n=25; 52.1%) were ultrasonographically detected. MRI did not give additional benefit over the ultrasonography. The ratio of associated anomalies in neural tube defect group was 25%. Two fetal neural tube defects with Down syndrome were remarkable. The rate of homozygous methylenetetrahydrofolate reductase c.677C &gt; T SNPs among the mothers of neural tube defect fetuses (n=20) was 15%. Comparing with gestationally matched healthy pregnancies, although maternal BMIs and periconceptional folate intake of neural tube defect group were significantly different, maternal serum folic acid, vitamin B12 and zinc levels were similar.Conclusion: The northwestern region appeared to be a relatively low prevalence area of Turkey for fetal neural tube defects. Any association with maternal serum folic acid, vitamin B12 and zinc levels could not be shown in this region.

Livedoid vasculopathy (LV) associated with hyperhomocysteinemia due to a homozygous methylene tetrahydrofolate reductase (MTHFR) C677T mutation: A case report

Livedoid vasculopathy (LV) associated with hyperhomocysteinemia due to a homozygous methylene tetrahydrofolate reductase (MTHFR) C677T mutation: A case report

The prevalence of homozygous MTHFR polymorphism(s) in a Turkish university hospital population that necessitated MTHFR polymorphism investigation

Background:Methylenetetrahydrofolate reductase (MTHFR) polymorphisms may cause various medical disorders through different mechanisms. We aimed to determine the allelic frequency and the prevalence of homozygous MTHFR polymorphisms in a tertiary university hospital population that necessitated MTHFR polymorphism investigation owing to various reasons.Methods:Our study consisted of 10449 patients who necessitated MTHFR polymorphism investigation owing to various reasons (coronary artery diseases, thrombotic events, epilepsy, migraine, repeated miscarriages, various obstetric complications) during 2008-2017.Results:The allelic frequency of MTHFR 677 and MTHFR 1298 mutations were 0.296 and 0.283 respectively. The prevalence of homozygous MTHFR C677T and MTHFR A1298C polymorphisms were 10.2 % and 11.1 %, respectively.Conclusions:MTHFR polymorphisms are more frequent than was expected and one should be cautious when drawing disorder specific conclusions.