A novel mutation in GCK gene: Beware of SGA child with diabetic mother.

MODY is a monogenic, autosomal dominant form of diabetes mellitus. MODY can be caused by mutations in several genes; glucokinase (GCK) accounts for 30-50% of the cases. The diagnosis can be suspected in early-onset diabetes with atypical features for type 1/type 2. Treatment is usually not recommended. A 5-year-old girl came to our attention for occasional episodes of hyperglycaemia. She was born at term, her birth weight was small for gestational age. At the beginning of her pregnancy, her mother was already on insulin therapy for impaired fasting glucose levels, detected before conception and confirmed in the first weeks of gestation. She was treated with insulin until the childbirth without further investigations. The patient was asymptomatic and in good clinical condition. Basal blood tests have shown a fasting plasma glucose of 125 mg/dl, an HbA1c of 6.5%. Antibodies against islet cells, anti-GAD and anti-ZNT8 antibodies were all negative. A 2-h oral glucose tolerance test was performed and underlined an impaired glucose tolerance. HLA haplotypes were screened, excluding susceptibility. GCK Sanger Sequencing identified a novel heterozygous variant. It is not described as a classical mutations. The analysis has been extended to the parents, finding out the same variant in her mother. To our knowledge this mutation has not been described previously; we believe that this variant is responsible for MODY2 due to FBG and Hb1Ac of all the affected members of family. We suggest high suspicion of an underlying GCK variant in SGA children with hyperglycaemia born to a diabetic mother.

Hemodynamic and Anatomic Variations Require an Adaptable Approach during Intra-Arterial Chemotherapy for Intraocular Retinoblastoma: Alternative Routes, Strategies, and Follow-Up.

BACKGROUND AND PURPOSE: Intra-arterial chemotherapy for retinoblastoma is not always a straightforward procedure, and it may require an adaptable approach. This study illustrates strategies used when the ophthalmic artery is difficult to catheterize or not visible, and it ascertains the effectiveness and safety of these strategies. MATERIALS AND METHODS: A retrospective study was performed on a series of 108 eyes affected by intraocular retinoblastoma and selected for intra-arterial chemotherapy (follow-up range, 6-82 months). We recognized 3 different patterns of drug delivery: a fixed pattern through the ophthalmic artery, a fixed pattern through branches of the external carotid artery, and a variable pattern through either the ophthalmic or the external carotid artery. RESULTS: We performed 448 sessions of intra-arterial chemotherapy, 83.70% of them through the ophthalmic artery and 16.29% via the external carotid artery. In 24.52% of eyes, the procedure was performed at least once through branches of the external carotid artery. In 73 eyes, the pattern of drug delivery was fixed through the ophthalmic artery; for 9 eyes, it was fixed through branches of the external carotid artery; and for 17 eyes, the pattern was variable. Statistical analysis did not show any significant difference in the clinical outcome of the eyes (remission versus enucleation) treated with different patterns of drug delivery. Adverse events could not be correlated with any particular pattern. CONCLUSIONS: Alternative routes of intra-arterial chemotherapy for intraocular retinoblastoma appear in the short term as effective and safe as the traditional drug infusion through the ophthalmic artery.

The superior horizontal pancreatic artery of Popova: a review and an anatomoradiological study of an important morphological variant of the pancreatica magna artery.

PURPOSE: The superior horizontal pancreatic artery was described in 1910, and after a few years, it was forgot by most investigators. This research is aimed to revive the description of this artery, describing course, pattern of branching and frequency. METHODS: More than 1,000 of angiographies including studies of the superior mesenteric artery, celiac trunk and its branches, were selected from the angiographic archives of the ex-institutes of Radiology of Siena, Rome (University of Sacro Cuore) and Perugia, and the arterial anatomy of the pancreas was studied. RESULTS: A pancreatic branch of the splenic artery running along the superior border of the pancreatic body and tail was observed in 25.93% of cases. This branch matched the description of the superior horizontal pancreatic artery and, when existing, replaced the pancreatica magna artery. For this reason, we considered the superior horizontal pancreatic artery as a variant of the pancreatica magna artery. Variable in caliber and importance, in most cases the superior horizontal pancreatic artery gave off descending branches that anastomosed with the inferior pancreatic artery. CONCLUSIONS: A superior horizontal pancreatic artery could be visualized more easily by selective angiography of the splenic artery. When coupled with the inferior pancreatic artery, the presence of the superior horizontal pancreatic artery outlined a longitudinally arranged pattern of blood supply of the distal pancreas that should be known. In particular circumstances, extended resections of the gland cutting both longitudinal arteries might jeopardize the surviving of the pancreas remnant.

Contrast-enhanced ultrasound assessment of complex cystic lesions in renal transplant recipients with acquired cystic kidney disease: preliminary experience.

We prospectively studied the potential value of contrast-enhanced ultrasound (CEUS) to characterize complex acquired cystic kidney disease (ACKD) or suspected solid renal masses, avoiding the risk of inducing acute kidney injury in 138 renal transplant recipients by contrast-enhanced computed tomography (CT). Forty-three cases (31%) had ACKD; 15 ACKD patients (35%) showed suspicious or nondiagnostic ultrasound. The latter subgroup underwent CEUS and, if the suspicion was confirmed, a contrast-enhanced CT. Thirty five lesions were identified in the 15 patients studied by CEUS. According to the Bosniak classification, 27 cysts were type I (BI), four type II (BII), two type III (BIII) with enhancement at the level of thickened septa; we also identified two solid enhancing lesions (BIV). We followed the BI and BII lesions with serial CEUS, while the remaining four cases underwent contrast-enhanced CT showing two solid lesions and two complex cysts with contrast enhancement in the septea. The four patients underwent surgical resection yielding three renal cell carcinomas one papillary carcinoma as the pathological findings. This preliminary study characterized solid nodules and BIII lesions for further evaluation by CT. CEUS seems to correctly characterize BI and BII cysts that are not clearly defined by standard ultrasound.

5-Methyltetrahydrofolate-homocysteine methyltransferase gene polymorphism (MTR) and risk of head and neck cancer.

The functional effect of the A>G transition at position 2756 on the MTR gene (5-methyltetrahydrofolate-homocysteine methyltransferase), involved in folate metabolism, may be a risk factor for head and neck squamous cell carcinoma (HNSCC). The frequency of MTR A2756G (rs1805087) polymorphism was compared between HNSCC patients and individuals without history of neoplasias. The association of this polymorphism with clinical histopathological parameters was evaluated. A total of 705 individuals were included in the study. The polymerase chain reaction-restriction fragment length polymorphism technique was used to genotype the polymorphism. For statistical analysis, the chi-square test (univariate analysis) was used for comparisons between groups and multiple logistic regression (multivariate analysis) was used for interactions between the polymorphism and risk factors and clinical histopathological parameters. Using univariate analysis, the results did not show significant differences in allelic or genotypic distributions. Multivariable analysis showed that tobacco and alcohol consumption (P < 0.05), AG genotype (P = 0.019) and G allele (P = 0.028) may be predictors of the disease and a higher frequency of the G polymorphic allele was detected in men with HNSCC compared to male controls (P = 0.008). The analysis of polymorphism regarding clinical histopathological parameters did not show any association with the primary site, aggressiveness, lymph node involvement or extension of the tumor. In conclusion, our data provide evidence that supports an association between the polymorphism and the risk of HNSCC.

5-Methyltetrahydrofolate-homocysteine methyltransferase gene polymorphism (MTR) and risk of head and neck cancer

The functional effect of the A>G transition at position 2756 on the MTR gene (5-methyltetrahydrofolate-homocysteine methyltransferase), involved in folate metabolism, may be a risk factor for head and neck squamous cell carcinoma (HNSCC). The frequency of MTR A2756G (rs1805087) polymorphism was compared between HNSCC patients and individuals without history of neoplasias. The association of this polymorphism with clinical histopathological parameters was evaluated. A total of 705 individuals were included in the study. The polymerase chain reaction-restriction fragment length polymorphism technique was used to genotype the polymorphism. For statistical analysis, the chi-square test (univariate analysis) was used for comparisons between groups and multiple logistic regression (multivariate analysis) was used for interactions between the polymorphism and risk factors and clinical histopathological parameters. Using univariate analysis, the results did not show significant differences in allelic or genotypic distributions. Multivariable analysis showed that tobacco and alcohol consumption (P < 0.05), AG genotype (P = 0.019) and G allele (P = 0.028) may be predictors of the disease and a higher frequency of the G polymorphic allele was detected in men with HNSCC compared to male controls (P = 0.008). The analysis of polymorphism regarding clinical histopathological parameters did not show any association with the primary site, aggressiveness, lymph node involvement or extension of the tumor. In conclusion, our data provide evidence that supports an association between the polymorphism and the risk of HNSCC.

Genetic variability of vascular endothelial growth factor and prognosis of head and neck cancer in a Brazilian population

Vascular endothelial growth factor (VEGF) is one of the most potent endothelial cell mitogens and plays a critical role in angiogenesis. Polymorphisms in this gene have been evaluated in patients with several types of cancer. The objectives of this study were to determine if there was an association of the -1154G/A polymorphism of the VEGF gene with head and neck cancer and the interaction of this polymorphism with lifestyle and demographic factors. Additionally, the distribution of the VEGF genotype was investigated with respect to the clinicopathological features of head and neck cancer patients. The study included 100 patients with histopathological diagnosis of head and neck squamous cell carcinoma. Patients with treated tumors were excluded. A total of 176 individuals 40 years or older were included in the control group and individuals with a family history of neoplasias were excluded. Analysis was performed after extraction of genomic DNA using the real-time PCR technique. No statistically significant differences between allelic and genotype frequencies of -1154G/A VEGF polymorphism were identified between healthy individuals and patients. The real-time PCR analyses showed a G allele frequency of 0.72 and 0.74 for patients and the control group, respectively. The A allele showed a frequency of 0.28 for head and neck cancer patients and 0.26 for the control group. However, analysis of the clinicopathological features showed a decreased frequency of the A allele polymorphism in patients with advanced (T3 and T4) tumors (OR = 0.36; 95 percentCI = 0.14-0.93; P = 0.0345). The -1154A allele of the VEGF gene may decrease the risk of tumor growth and be a possible biomarker for head and neck cancer. This polymorphism is associated with increased VEGF production and may have a prognostic importance.

Genetic variability of vascular endothelial growth factor and prognosis of head and neck cancer in a Brazilian population.

Vascular endothelial growth factor (VEGF) is one of the most potent endothelial cell mitogens and plays a critical role in angiogenesis. Polymorphisms in this gene have been evaluated in patients with several types of cancer. The objectives of this study were to determine if there was an association of the -1154G/A polymorphism of the VEGF gene with head and neck cancer and the interaction of this polymorphism with lifestyle and demographic factors. Additionally, the distribution of the VEGF genotype was investigated with respect to the clinicopathological features of head and neck cancer patients. The study included 100 patients with histopathological diagnosis of head and neck squamous cell carcinoma. Patients with treated tumors were excluded. A total of 176 individuals 40 years or older were included in the control group and individuals with a family history of neoplasias were excluded. Analysis was performed after extraction of genomic DNA using the real-time PCR technique. No statistically significant differences between allelic and genotype frequencies of -1154G/A VEGF polymorphism were identified between healthy individuals and patients. The real-time PCR analyses showed a G allele frequency of 0.72 and 0.74 for patients and the control group, respectively. The A allele showed a frequency of 0.28 for head and neck cancer patients and 0.26 for the control group. However, analysis of the clinicopathological features showed a decreased frequency of the A allele polymorphism in patients with advanced (T3 and T4) tumors (OR = 0.36; 95%CI = 0.14-0.93; P = 0.0345). The -1154A allele of the VEGF gene may decrease the risk of tumor growth and be a possible biomarker for head and neck cancer. This polymorphism is associated with increased VEGF production and may have a prognostic importance.

Double aneuploidy (48,XXY,+21) of maternal origin in a child born to a 13-year-old mother: evaluation of the maternal folate metabolism.

The occurrence of non-mosaic double trisomy is exceptional in newborns. In this paper, a 48,XXY,+21 child, the parental origin of the extra chromosomes and the evaluation of the maternal folate metabolism are presented. The infant was born to a 13-year-old mother and presented with the typical clinical features of Down syndrome (DS). The origin of the additional chromosomes was maternal and most likely resulted from errors during the first meiotic division. Molecular analysis of 12 genetic polymorphisms involved in the folate metabolism revealed that the mother is heterozygous for the MTHFR C677T and TC2 A67G polymorphisms, and homozygous for the mutant MTRR A66G polymorphism. The maternal homocysteine concentration was 4.7 miromol/L, a value close to the one considered as a risk factor for DS in our previous study. Plasma methylmalonic acid and serum folate concentrations were 0.17 micromol/L and 18.4 ng/mL, respectively. It is possible that the presence of allelic variants for the folate metabolism and Hey concentration might have favored errors in chromosomal disjunction during gametogenesis in this young mother. To our knowledge, this is the first patient with non-mosaic Down-Klinefelter born to a teenage mother, resulting from a rare fertilization event combining an abnormal 25,XX,+21 oocyte and a 23,Y spermatozoon.

Prescriptions of NSAIDs to patients undergoing third molar surgery : an observational, prospective, multicentre survey.

BACKGROUND AND OBJECTIVES: Surgical extraction of an impacted third molar is generally followed by acute post-operative pain that has been shown to be primarily inflammatory. Thus, use of NSAIDs in this context is appropriate and has been shown to be effective. Several drugs are employed for this purpose, but no information exists on the reasons why preference is given to one rather than another. The principal objective of this study was to evaluate the pattern of administration of NSAIDs in patients undergoing surgery for impacted third molar extraction. The study also aimed to collect information on the efficacy, onset and duration of the analgesic effect of routinely prescribed NSAIDs and to assess the duration of treatment with these drugs and their tolerability. METHODS: This was an observational, multicentre, prospective survey. A total of 616 patients (38% male and 62% female) from the Italian Stomatology Clinics of the Universities of Bologna, Brescia, Cagliari, Chieti, Pavia, Pisa, Siena and Varese and from the Department of Oral and Maxillo-Facial Surgery of Semmelweis University, Budapest, were eligible for the study. Patients were evaluated over the 7 days following surgical extraction. NSAIDs were prescribed according to the normal prescribing habits of the centre and physician involved. The main outcomes of interest in the survey were the efficacy, onset and duration of analgesic effect, duration of therapy, and tolerability of the NSAIDs prescribed. RESULTS: Nimesulide was the most prescribed NSAID (68%), followed by diclofenac, ketoprofen and ibuprofen. Because of the low proportion of patients receiving other NSAIDs, these patients were considered a single treatment group for evaluation purposes. Nimesulide, especially when given before patients started experiencing pain after surgery, was more effective than other NSAIDs in reducing the severity of pain on the day of surgery, in delaying the time to maximum intensity of pain, in providing complete pain relief and in prolonging the duration of analgesic effect on the day of surgery. These results are consistent with the known anti-inflammatory and analgesic actions of nimesulide and with the important role of inflammation in the onset of pain after this type of surgery. CONCLUSION: These results confirm nimesulide as an effective reference drug for the treatment of post-operative dental pain and show that it has a positive benefit/risk profile in this setting.

Pharmacogenetics of mycophenolate mofetil: a promising different approach to tailoring immunosuppression?

Since the Human Genome Project, the evaluation of the effectiveness and safety of some medications has become partially connected to innate metabolic patterns. Thus, genes that encode receptors and enzymes could play different roles in metabolism, according to their polymorphisms. Especially in organ transplantation, some of the available medications used in immunosuppressive therapy have a narrow therapeutic index, affecting the individual response to these drugs. This review focuses on the polymorphism of genes that encode enzymes of the uridino-glucuronosyltransferase (UGT) family, responsible for the bioavailability of mycophenolic acid, the active metabolite of mycophenolate mofetil (MMF), used as an immunosuppressant in solid organ transplantation. The increasing literature data regarding the pharmacogenetics of UGT and MMF suggest that enzyme polymorphism can explain the factors which influence the occurrence of side effects in patients receiving MMF as drug transplant therapy.

Influence of UDP-glucuronosyltransferase polymorphisms on mycophenolate mofetil-induced side effects in kidney transplant patients.

Mycophenolate mofetil (MMF) is an immunosuppressive prodrug approved for use in transplantation. Its active metabolite, mycophenolic acid, is mainly metabolized by UDP-glucuronosyltransferase (UGT) enzymes. In this study, we retrospectively analyzed 74 kidney transplant patients who had been prescribed MMF as part of their immunosuppression regimen. Polymorphisms in UGT1A8 (-999C > T, codon 255A > G, codon 277G > A) were correlated with the occurrence of side effects, such as diarrhea, blood disorders, and infections. The infectious episodes were more frequently observed among individuals receiving MMF (2 g/d) who carryied the variant UGT1A8 codon 277A (P = .031), the haplotype UGT1A8H5 (-999C/codon 55A/codon 277A; P = .02), and the diplotype UGT1A8H2/H5 (-999CC/codon 255AA/codon 277GA; P = .015). The molecular data from this study suggest that UGT polymorphisms may be a factor influencing clinical outcomes among patients receiving MMF for transplant therapy; however, larger studies are warranted.

Role of glutathione s-transferase polymorphisms and chronic allograft dysfunction.

Polymorphisms within genes encoding glutathione S-transferases (GSTs) may affect responses against damage induced by oxidative stress and therefore play a role to prevent chronic allograft dysfunction (CAD). In the present study, we estimated the frequencies of GSTM1- and GSTT1-null genotypes among 227 renal transplant recipients seeking to establish an association with CAD. Patients persistently displaying serum creatinine (sCr) values < or = 1.5 mg/dL, measured creatinine clearances (CLcr) > or = 50 mL/min/1.73 m(2), and 24-hour proteinuria < or = 500 mg were classified as normal graft function (NF; n = 107). In contrast, the CAD group (n = 120) presented sCr > 1.5 mg/dL, CLcr < 50 mL/min/1.73 m(2), and proteinuria > 500 mg. The GSTM1 and GSTT1 polymorphisms were evaluated by the multiplex polymerase chain reaction. The frequencies of GSTT1-null genotypes in NF and CAD cohorts were 15% and 24.2%, respectively (P = .057), while GSTM1-null genotypes in the same groups of patients were 44% and 46.7% (P = .389). A combination of null genotypes for GSTT1 and GSTM1 was observed in 9.2% of patients with CAD and in 5.6% of those with NF (P = .449). This study did not show an association of either GSTT1- and GSTM1-null genotypes with CAD. It is likely that development and progression of CAD are determined by a combination of complex genetic traits resulting from the interplay of several genes rather than a single gene.

Effect of whole bone marrow cell infusion in the progression of experimental chronic renal failure.

INTRODUCTION: The therapeutic potential of adult stem cells for the treatment of chronic diseases is becoming increasingly evident over the last few years. In the present study, we sought to assess whether the infusion of bone marrow-derived mononuclear cells (MoSCs) and mesenchymal cells (MSCs) could reduce/stabilize the rate of progression of chronic renal failure (CRF) in rats. METHODS: We used the 5/6 renal mass reduction model to induce chronic renal failure in male Wistar rats. Renal function was assessed by measurements of serum creatinine (sCr), creatinine clearance (Clcr), and 24-hour proteinuria at baseline as well as 60 and 120 days after surgery. MoSCs and MSCs obtained from bone marrow aspirates were separated by the Ficoll-Hypaque method. After a 12- to 14-day culture, 1.5 x 10(6) MSCs and the same number of MoSCs were injected into the renal parenchyma of the remanant kidney of rats with CRF on the day of surgery. RESULTS: Among the control group, at day 120, the results were sCr = 1.31 +/- 0.5 mg/dL, Clcr = 0.64 +/- 0.35 mL/min, and proteinuria = 140.0 +/- 57.7 mg/24 h. Rats treated with MoSCs at day 120 had sCr = 0.81 +/- 0.20 mg/dL, Clcr = 1.05 +/- 0.26 mL/min, and proteinuria = 61 +/- 46.5 mg/24 h, while rats injected with MSCs had sCr = 0.95 +/- 0.1 mg/dL, Clcr = 0.68 +/- 0.24 mL/min, and proteinuria = 119.2 +/- 50.0 mg/24 h. Analysis of the progression to CRF showed that the treatment significantly reduced the rate of decline in Clcr after treatment with MoSc: control: -0.0049 +/- 0.0024 mL/min/d versus MSC: - 0.0013 +/- 0.0017 mL/min/d versus MoSC: +0.0002 +/- 0.0016 mL/min/d (P = .017). Proteinuria tended to be lower among the treated groups. Histological scores of chronic damage were not different, but distinct patterns of chronic lesions were observed among treated rats. CONCLUSION: Our results showed that progression of CRF in rats could be slowed/stabilized by intrarenal parenchymal injection of MoSCs. A trend toward reduction in the progression rate of CRF was also observed with injection of MSCs.

Genetic polymorphisms involved in folate metabolism and elevated plasma concentrations of homocysteine: maternal risk factors for Down syndrome in Brazil.

The aim of the present study was to investigate the effect of polymorphisms C677T and A1298C in the methylenetetrahydrofolate reductase (MTHFR) gene, A2756G in methionine synthase reductase (MTR) gene and A80G in reduced folate carrier 1 (RFC1) gene, and plasma homocysteine (Hcy), on the maternal risk for Down syndrome (DS). Seventy-two DS mothers and 194 mothers who had no children with DS were evaluated. The investigation of the MTHFR C677T, MTR A2756G and RFC1 A80G polymorphisms was performed by polymerase chain reaction and enzyme digestion and the MTHFR A1298C polymorphism by allele-specific polymerase chain reaction. Hcy quantification was carried out by liquid chromatography-tandem mass spectrometry. The median number of polymorphic alleles for the four loci tested was greater in DS mothers compared to the control group, and the presence of three or more polymorphic alleles increased the risk for having a child with DS 1.74 times. Elevated maternal risk for DS was also observed when plasma Hcy concentration was higher than 4.99 micromol/L. In conclusion, the presence of three or more polymorphic alleles for MTHFR C677T, MTHFR A1298C, MTR A2756G, and RFC1 A80G, and plasma Hcy concentrations higher than 4.99 micromol/L are maternal risk factors for DS.

Genetic polymorphisms involved in folate metabolism and elevated plasma concentrations of homocysteine: maternal risk factors for Down syndrome in Brazil

The aim of the present study was to investigate the effect of polymorphisms C677T and A1298C in the methylenetetrahydrofolate reductase (MTHFR) gene, A2756G in methionine synthase reductase (MTR) gene and A80G in reduced folate carrier 1 (RFC1) gene, and plasma homocysteine (Hcy), on the maternal risk for Down syndrome (DS). Seventy-two DS mothers and 194 mothers who had no children with DS were evaluated. The investigation of the MTHFR C677T, MTR A2756G and RFC1 A80G polymorphisms was performed by polymerase chain reaction and enzyme digestion and the MTHFR A1298C polymorphism by allele-specific polymerase chain reaction. Hcy quantification was carried out by liquid chromatography-tandem mass spectrometry. The median number of polymorphic alleles for the four loci tested was greater in DS mothers compared to the control group, and the presence of three or more polymorphic alleles increased the risk for having a child with DS 1.74 times. Elevated maternal risk for DS was also observed when plasma Hcy three or more polymorphic alleles for MTHFR C677T, MTHFR A1298C, MTR A2756G, and RFC1 A80G, and plasma Hcy concentrations higher than 4.99 mi mol/L are maternal risk factors for DS.

The MTR A2756G polymorphism is associated with an increase of plasma homocysteine concentration in Brazilian individuals with Down syndrome

Individuals with Down syndrome (DS) present decreased homocysteine (Hcy) concentration, reflecting a functional folate deficiency secondary to overexpression of the cystathionine ß-synthase gene. Since plasma Hcy may be influenced by genetic polymorphisms, we evaluated the influence of C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR), of A2756G polymorphism in the methionine synthase gene (MTR), and of A80G polymorphism in the reduced folate carrier 1 gene on Hcy concentrations in Brazilian DS patients. Fifty-six individuals with free trisomy 21 were included in the study. Plasma Hcy concentrations were measured by liquid chromatography_tandem mass spectrometry with linear regression coefficient r² = 0.9996, average recovery between 92.3 to 108.3 percent and quantification limits of 1.0 µmol/L. Hcy concentrations >15 µmol/L were considered to characterize hyperhomocystinemia. Genotyping for the polymorphisms was carried out by polymerase chain reaction followed by enzyme digestion and allele-specific polymerase chain reaction. The mean Hcy concentration was 5.2 ± 3.3 µmol/L. There was no correlation between Hcy concentrations and age, gender or MTHFR C677T, A1298C and reduced folate carrier 1 A80G genotype. However, Hcy concentrations were significantly increased in the MTR 2756AG heterozygous genotype compared to the MTR 2756AA wild-type genotype. The present results suggest that the heterozygous genotype MTR 2756AG is associated with the increase in plasma Hcy concentrations in this group of Brazilian patients with DS.

The MTR A2756G polymorphism is associated with an increase of plasma homocysteine concentration in Brazilian individuals with Down syndrome.

Individuals with Down syndrome (DS) present decreased homocysteine (Hcy) concentration, reflecting a functional folate deficiency secondary to overexpression of the cystathionine ss-synthase gene. Since plasma Hcy may be influenced by genetic polymorphisms, we evaluated the influence of C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR), of A2756G polymorphism in the methionine synthase gene (MTR), and of A80G polymorphism in the reduced folate carrier 1 gene on Hcy concentrations in Brazilian DS patients. Fifty-six individuals with free trisomy 21 were included in the study. Plasma Hcy concentrations were measured by liquid chromatography_tandem mass spectrometry with linear regression coefficient r(2) = 0.9996, average recovery between 92.3 to 108.3% and quantification limits of 1.0 micromol/L. Hcy concentrations >15 micromol/L were considered to characterize hyperhomocystinemia. Genotyping for the polymorphisms was carried out by polymerase chain reaction followed by enzyme digestion and allele-specific polymerase chain reaction. The mean Hcy concentration was 5.2 +/- 3.3 micromol/L. There was no correlation between Hcy concentrations and age, gender or MTHFR C677T, A1298C and reduced folate carrier 1 A80G genotype. However, Hcy concentrations were significantly increased in the MTR 2756AG heterozygous genotype compared to the MTR 2756AA wild-type genotype. The present results suggest that the heterozygous genotype MTR 2756AG is associated with the increase in plasma Hcy concentrations in this group of Brazilian patients with DS.