Sodium-glucose cotransporter-2 inhibitor therapy in kidney transplant patients with type 2 or post-transplant diabetes: an observational multicentre study.

Background: Sodium-glucose cotransporter-2 inhibitors (SGLT2is) have cardioprotective and renoprotective effects. However, experience with SGLT2is in diabetic kidney transplant recipients (DKTRs) is limited. Methods: This observational multicentre study was designed to examine the efficacy and safety of SGLT2is in DKTRs. The primary outcome was adverse effects within 6 months of SGLT2i treatment. Results: Among 339 treated DKTRs, adverse effects were recorded in 26%, the most frequent (14%) being urinary tract infection (UTI). In 10%, SGLT2is were suspended mostly because of UTI. Risk factors for developing a UTI were a prior episode of UTI in the 6 months leading up to SGLT2i use {odds ratio [OR] 7.90 [confidence interval (CI) 3.63-17.21]} and female sex [OR 2.46 (CI 1.19-5.03)]. In a post hoc subgroup analysis, the incidence of UTI emerged as similar in DKTRs treated with SGLT2i for 12 months versus non-DKTRs (17.9% versus 16.7%). Between baseline and 6 months, significant reductions were observed in body weight [-2.22 kg (95% CI -2.79 to -1.65)], blood pressure, fasting glycaemia, haemoglobin A1c [-0.36% (95% CI -0.51 to -0.21)], serum uric acid [-0.44 mg/dl (95% CI -0.60 to -0.28)] and urinary protein:creatinine ratio, while serum magnesium [+0.15 mg/dl (95% CI 0.11-0.18)] and haemoglobin levels rose [+0.44 g/dl (95% CI 0.28-0.58]. These outcomes persisted in participants followed over 12 months of treatment. Conclusions: SGLT2is in kidney transplant offer benefits in terms of controlling glycaemia, weight, blood pressure, anaemia, proteinuria and serum uric acid and magnesium. UTI was the most frequent adverse effect. According to our findings, these agents should be prescribed with caution in female DKTRs and those with a history of UTI.

Anti-myeloperoxidase and proteinase 3 antibodies for nephritis flare prediction in anti-neutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND: The value of myeloperoxidase (MPO) and proteinase 3 (PR3) antibody titres in the assessment of renal disease activity and flare prediction in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is not well known. METHODS: We performed a retrospective study including 113 AVV patients with renal biopsy-proven pauci-immune necrotizing glomerulonephritis from seven Spanish hospitals. The main inclusion criteria were assessment of MPO antibodies using multiplex flow immunoassay and PR3 antibody measurements using immunoassay chemiluminescence with an identical range of values for all participating centres. RESULTS: Serum MPO antibodies 3 ± 1.2 months before relapse were higher in patients who relapsed [19.2 ± 12.2 versus 3.2 ± 5.1 antibody index (AI); P < 0.001]. The discrimination value of MPO antibodies 3 months before renal relapse had an area under the receiver operating characteristics curve (AUC) of 0.82 [95% confidence interval (CI) 0.73-0.92; P < 0.001]. ΔMPO antibodies (change in antibodies titration 6 months before relapse) were higher in patients who relapsed (8.3 ± 12 versus 0.9 ± 3.1 AI; P = 0.001). The discrimination value of ΔMPO had an AUC of 0.76 (95% CI 0.63-0.88; P < 0.001). The positive predictive value of renal relapse in PR3 patients is 100% and the negative predictive value of renal relapse in patients with PR3-positive titres is 57.1%. Serum PR3 antibodies were higher in patients who relapsed 2.8 ± 1.4 months before relapse (58.6 ± 24.6 versus 2.0 ± 0.6 AI; P < 0.001). CONCLUSIONS: MPO level monitoring using multiplex flow immunoassay and PR3 measurements using immunoassay chemiluminescence are useful and sensitive tools for the prediction of renal relapse in the follow-up of AAV patients with renal disease and relevant surrogate markers of renal disease activity.

Right ventricular dysfunction and right ventricular-arterial uncoupling at admission increase the in-hospital mortality in patients with COVID-19 disease.

BACKGROUND: Coronavirus disease 2019 (COVID-19) frequently involves cardiovascular manifestations such as right ventricular (RV) dysfunction and alterations in pulmonary hemodynamics. We evaluated the application of the critical care ultrasonography ORACLE protocol to identify the most frequent alterations and their influence on adverse outcomes, especially those involving the RV (dilatation and dysfunction). METHODS: This cross-sectional study included 204 adult patients with confirmed COVID-19 admitted at three centers. Echocardiography and lung ultrasound images were acquired on admission using the ORACLE ultrasonography algorithm. RESULTS: Two-hundred and four consecutive patients were evaluated: 22 (11.9%) demonstrated a fractional shortening of < 35%; 33 (17.1%) a tricuspid annular plane systolic excursion (TAPSE) of < 17 mm; 26 (13.5%) a tricuspid peak systolic S wave tissue Doppler velocity of < 9.5 cm/sec; 69 (37.5%) a RV basal diameter of > 41 mm; 119 (58.3%) a pulmonary artery systolic pressure (PASP) of > 35 mm Hg; and 14 (11%) a TAPSE/PASP ratio of < .31. The in-hospital mortality rate was 37.6% (n = 71). Multiple logistic regression modeling showed that PASP > 35 mm Hg, RV FS of < 35%, TAPSE < 17 mm, RV S wave < 9.5, and TAPSE/PASP ratio < .31 mm/mm Hg were associated with this outcome. PASP and the TAPSE/PASP ratio had the lowest feasibility of being obtained among the investigators (62.2%). CONCLUSION: The presence of RV dysfunction, pulmonary hypertension, and alteration of the RV-arterial coupling conveys an increased risk of in-hospital mortality in patients presenting with COVID-19 upon admission; therefore, searching for these alterations should be routine. These parameters can be obtained quickly and safely with the ORACLE protocol.

Increased non-attendance at epilepsy clinic in patients with neuropsychiatric comorbidities: A prospective study.

BACKGROUND: In patients with epilepsy, regular follow-up is vital for adequate seizure control, antiseizure drugs' (ASDs) side effects, psychiatric comorbidities, and planning for epilepsy surgery. Non-attendance creates barriers to adequate patient care, inefficient allocation of resources, loss of income, and unnecessary emergency department visits due to lack of seizure control. This study aimed to determine the causes and sociodemographic characteristics of the non-attendant population at the Epilepsy Clinic. METHODS: A prospective and observational study was carried out on patients treated at the Epilepsy Clinic of the National Institute of Neurology and Neurosurgery (NINN) in Mexico from August 2015 to June 2016. A phone interview was made with all those patients who did not attend the epilepsy consultation. This call incorporated ad hoc questions to meet the objectives of this study. RESULTS: During the study period, 1299 patients had an appointment at the epilepsy clinic, where 233 (17.9%) patients missed their consultation, 123 (52.8%) were male, mean age was 35.9 ±â€¯14.42 years. The most frequent cause of non-attendance was forgetfulness of the appointment in 62 patients (26.6%). Two patients died; no patient was reported to have experienced SUDEP. Non-attendant patients showed statistically significant overall prevalence of psychiatric comorbidities (41.6%), particularly depression, anxiety, and interictal psychosis. CONCLUSION: Information on non-attendance at various specialist consultations is scarce, and to our knowledge, this is the first study to address non-attendance in patients with epilepsy in Latin America. Improving hospital protocols to reduce non-attendance can increase patient adherence to follow-up, ultimately improving the quality of care in the epilepsy clinic.

Cerebellar Degeneration Signature in Huntington's Disease.

Recent findings suggest a significant effect of the cerebellar circuit deterioration on the clinical manifestation of Huntington's disease, calling for a better understanding of the cerebellar degeneration in this disorder. Recent brain imaging analyses have provided conflicting results regarding the cerebellar changes during the progression of this disease. To help in resolving this controversy, we examined the cerebellar gray matter structural integrity from a cohort of HD patients. Whole brain voxel-based morphometry (VBM) and spatially unbiased atlas template of the human cerebellum (SUIT) analyses were done from T1-weighted brain images. Our results showed a significant cerebellar degeneration without any sign of volume increase. The highest cerebellar degeneration was identified in Crus I right lobule, Crus II bilaterally, and left VIIb, and left VIIIa lobules. The cerebellar degeneration signature, which controls for severity of degeneration, showed a degeneration pattern that included regions I-IV, Crus II, VIIb, VIIIa, VIIIb and X.

Transthoracic echocardiography during prone position ventilation: Lessons from the COVID-19 pandemic.

Objective: The current coronavirus disease 2019 (COVID-19 outbreak) demands an increased need for hospitalizations in emergency departments (EDs) and critical care units. Owing to refractory hypoxemia, prone position ventilation has been used more frequently and patients will need repeated hemodynamic assessments. Our main objective was to show the feasibility of obtaining images to measure multiple parameters with transthoracic echocardiography during the prone position ventilation. Methods: We enrolled 15 consecutive mechanically ventilated patients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that required prone position ventilation as a rescue maneuver for refractory hypoxemia. The studies were performed by 2 operators with training in critical care echocardiography. Measurements were done outside the patient's room and the analysis of the images was performed by 3 cardiologists with training in echocardiography. Results: Adequate image acquisition of the left ventricle was possible in all cases; we were not able to visualize the right ventricular free wall only in 1 patient. The mean tricuspid annular plane systolic excursion was 17.8 mm, tricuspid peak systolic S wave tissue Doppler velocity 11.5 cm/s, and the right ventricular basal diameter 36.6 mm; left ventricle qualitative function was reduced in 6 patients; pericardial effusion or valvular abnormalities were not observed. Conclusion: We showed that echocardiographic images can be obtained to measure multiple parameters during the prone position ventilation. This technique has special value in situations where there is sudden hemodynamic deterioration and it is not possible to return the patient in the supine position.

Critical care ultrasonography during COVID-19 pandemic: The ORACLE protocol.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is characterized by severe lung involvement and hemodynamic alterations. Critical care ultrasonography is vital because it provides real time information for diagnosis and treatment. Suggested protocols for image acquisition and measurements have not yet been evaluated. METHODS: This cross-sectional study was conducted at two centers from 1 April 2020 to 30 May 2020 in adult patients with confirmed COVID-19 infection admitted to the critical care unit. Cardiac and pulmonary evaluations were performed using the ORACLE protocol, specifically designed for this study, to ensure a structured process of image acquisition and limit staff exposure to the infection. RESULTS: Eighty-two consecutively admitted patients were evaluated. Most of the patients were males, with a median age of 56 years, and the most frequent comorbidities were hypertension and type 2 diabetes, and 25% of the patients had severe acute respiratory distress syndrome. The most frequent ultrasonographic findings were elevated pulmonary artery systolic pressure (69.5%), E/e' ratio > 14 (29.3%), and right ventricular dilatation (28%) and dysfunction (26.8%). A high rate of fluid responsiveness (82.9%) was observed. The median score (19 points) on pulmonary ultrasound did not reveal any variation between the groups. Elevated pulmonary artery systolic pressure was associated with higher in-hospital mortality. CONCLUSION: The ORACLE protocol was a feasible, rapid, and safe bedside tool for hemodynamic and respiratory evaluation of patients with COVID-19. Further studies should be performed on the alteration in pulmonary hemodynamics and right ventricular function and its relationship with outcomes.

Extensive cerebellar and thalamic degeneration in spinocerebellar ataxia type 10.

INTRODUCTION: Spinocerebellar ataxia type 10 (SCA10) is a hereditary neurodegenerative disorder caused by repeat expansions in the ATXN10 gene. Patients present with cerebellar ataxia frequently accompanied by seizures. Even though loss of cerebellar Purkinje neurons has been described, its brain degeneration pattern is unknown. Our aim was to characterize the gray and white matter degeneration patterns in SCA10 patients and the association with clinical features. METHODS: We enrolled 18 patients with molecular diagnosis of SCA10 and 18 healthy individuals matched for age and sex. All participants underwent brain MRI including high-resolution anatomical and diffusion images. Whole-brain Tract-Based Spatial Statistics (TBSS) and Voxel-Based Morphometry (VBM) were performed to identify white and grey matter degeneration respectively. A second analysis in the cerebellum identified the unbiased pattern of degeneration. Motor impairment was assessed using the SARA Scale. RESULTS: TBSS analysis in the patient group revealed white matter atrophy exclusively in the cerebellum. VBM analysis showed extensive grey matter degeneration in the cerebellum, brainstem, thalamus, and putamen. Significant associations between cerebellar degeneration and SARA scores were found. Additionally, degeneration in thalamic GM and WM in the cerebellar lobule VI were significantly associated with the presence of seizures. CONCLUSION: The results show that besides cerebellum and brainstem, brain degeneration in SCA10 includes predominantly the putamen and thalamus; involvement of the latter is strongly associated with seizures. Analysis of the unbiased degeneration pattern in the cerebellum suggests lobules VIIIb, IX, and X as the primary cerebellar targets of the disease, which expands to the anterior lobe in later stages.

Membrane Attack Complex and Factor H in Humans with Acute Kidney Injury.

BACKGROUND AND AIMS: Complement system seems to play an important role in the pathogenesis of Acute Kidney Injury (AKI). The aim of this study was to investigate the role of complement system in the pathogenesis of human AKI. For this purpose, we studied Membrane Attack Complex (MAC) and factor H in plasma and kidney tissue in AKI. METHODS: Plasmatic concentrations of MAC and Factor H were studied in patients with hospital-acquired AKI and their respective controls. MAC and Factor H expression and localization within the kidney were studied by immunohistochemistry in kidney tissue samples from autopsies. Demographical, past medical, and laboratory data in patients on admission and 3 years after discharge were recorded. RESULTS: Plasmatic MAC concentrations were significantly higher in AKI-patients (5848±3604 vs 3703±1483 mAU/mL, p< 0.01), mainly in the severe cases, as measured by the need of renal replacement therapy, non-recovery of renal function, RIFLE classification and CKD development. MAC deposition was observed in tubular epithelial cell basal membranes, showing a larger number of tubules with MAC deposition, larger perimeter of affected tubules and greater intensity of MAC immunostaining in AKI patients. Factor H concentrations were higher in AKI patients (0.86±0.05 vs 0.60±0.04 mg/mL, p=0.007), showing a strong positive association with plasmatic MAC (r=0.7, p< 0.01)). Factor H immunostaining showed a tubular cytoplasmic pattern, with significant variations in the staining intensity, associated with the severity of histologic damage. CONCLUSION: Our data confirm that complement system is involved in human AKI, through the lytic action of MAC in tubular epithelial cells. These results suggest that complement system activation in AKI could be related with CKD development.

Variant Intestinal-Cell Kinase in Juvenile Myoclonic Epilepsy.

BACKGROUND: In juvenile myoclonic epilepsy, data are limited on the genetic basis of networks promoting convulsions with diffuse polyspikes on electroencephalography (EEG) and the subtle microscopic brain dysplasia called microdysgenesis. METHODS: Using Sanger sequencing, we sequenced the exomes of six members of a large family affected with juvenile myoclonic epilepsy and confirmed cosegregation in all 37 family members. We screened an additional 310 patients with this disorder for variants on DNA melting-curve analysis and targeted real-time DNA sequencing of the gene encoding intestinal-cell kinase ( ICK). We calculated Bayesian logarithm of the odds (LOD) scores for cosegregating variants, odds ratios in case-control associations, and allele frequencies in the Genome Aggregation Database. We performed functional tests of the effects of variants on mitosis, apoptosis, and radial neuroblast migration in vitro and conducted video-EEG studies in mice lacking a copy of Ick. RESULTS: A variant, K305T (c.914A→C), cosegregated with epilepsy or polyspikes on EEG in 12 members of the family affected with juvenile myoclonic epilepsy. We identified 21 pathogenic ICK variants in 22 of 310 additional patients (7%). Four strongly linked variants (K220E, K305T, A615T, and R632X) impaired mitosis, cell-cycle exit, and radial neuroblast migration while promoting apoptosis. Tonic-clonic convulsions and polyspikes on EEG resembling seizures in human juvenile myoclonic epilepsy occurred more often in knockout heterozygous mice than in wild-type mice (P=0.02) during light sleep with isoflurane anesthesia. CONCLUSIONS: Our data provide evidence that heterozygous variants in ICK caused juvenile myoclonic epilepsy in 7% of the patients included in our analysis. Variant ICK affects cell processes that help explain microdysgenesis and polyspike networks observed on EEG in juvenile myoclonic epilepsy. (Funded by the National Institutes of Health and others.).

Association of polymorphisms and reduced expression levels of the NR4A2 gene with Parkinson's disease in a Mexican population.

INTRODUCTION: The NR4A2 transcription factor is important in the development, survival and phenotype of dopaminergic neurons and it is postulated as a possible biomarker for Parkinson's disease (PD). Therefore, our aim was to analyze in a sample of a Mexican population with idiopathic PD, mutations (in two hotspot mutation regions) and two polymorphisms (rs34884856 in promotor and rs35479735 intronic regions) of the NR4A2 gene. We also evaluate the levels of NR4A2 gene expression in peripheral blood for a Mexican population, and identify whether they are associated with NR4A2 gene polymorphisms. METHODS: We conducted a case-control study, which included 227 idiopathic PD cases and 454 unrelated controls. Genetic variants of the NR4A2 gene were genotyped by high-resolution melting (HRM) and validated by an automated sequencing method. The gene expression was performed in peripheral blood using a real-time polymerase chain reaction. RESULTS: The rs35479735 polymorphism was associated with a higher risk of developing PD. In addition, NR4A2 gene expression was significantly decreased in patients with PD. Linkage disequilibrium analysis showed a haplotype H4 (3C-3G) that showed lower levels of expression, and contained the risk alleles for both polymorphisms. CONCLUSIONS: In summary, this is the first study in a Mexican population that considers the analysis of NR4A2 in patients with PD. An association was identified between genotype and mRNA expression levels of NR4A2 in patients with PD. These results suggest that polymorphisms and expression of the NR4A2 gene could play an important role in the risk of developing PD in Mexican populations.

EFHC1 variants in juvenile myoclonic epilepsy: reanalysis according to NHGRI and ACMG guidelines for assigning disease causality.

PURPOSE: EFHC1 variants are the most common mutations in inherited myoclonic and grand mal clonic-tonic-clonic (CTC) convulsions of juvenile myoclonic epilepsy (JME). We reanalyzed 54 EFHC1 variants associated with epilepsy from 17 cohorts based on National Human Genome Research Institute (NHGRI) and American College of Medical Genetics and Genomics (ACMG) guidelines for interpretation of sequence variants. METHODS: We calculated Bayesian LOD scores for variants in coinheritance, unconditional exact tests and odds ratios (OR) in case-control associations, allele frequencies in genome databases, and predictions for conservation/pathogenicity. We reviewed whether variants damage EFHC1 functions, whether efhc1-/- KO mice recapitulate CTC convulsions and "microdysgenesis" neuropathology, and whether supernumerary synaptic and dendritic phenotypes can be rescued in the fly model when EFHC1 is overexpressed. We rated strengths of evidence and applied ACMG combinatorial criteria for classifying variants. RESULTS: Nine variants were classified as "pathogenic," 14 as "likely pathogenic," 9 as "benign," and 2 as "likely benign." Twenty variants of unknown significance had an insufficient number of ancestry-matched controls, but ORs exceeded 5 when compared with racial/ethnic-matched Exome Aggregation Consortium (ExAC) controls. CONCLUSIONS: NHGRI gene-level evidence and variant-level evidence establish EFHC1 as the first non-ion channel microtubule-associated protein whose mutations disturb R-type VDCC and TRPM2 calcium currents in overgrown synapses and dendrites within abnormally migrated dislocated neurons, thus explaining CTC convulsions and "microdysgenesis" neuropathology of JME.Genet Med 19 2, 144-156.

High-dose versus low-dose valproate for the treatment of juvenile myoclonic epilepsy: Going from low to high.

Juvenile myoclonic epilepsy (JME) is a genetic generalized epilepsy accounting for 3-12% of adult cases of epilepsy. Valproate has proven to be the first-choice drug in JME for controlling the most common seizure types: myoclonic, absence, and generalized tonic-clonic (GTC). In this retrospective study, we analyzed seizure outcome in patients with JME using valproate monotherapy for a minimum period of one year. Low valproate dose was considered to be 1000mg/day or lower, while serum levels were considered to be low if they were at or below 50mcg/dl. One hundred three patients met the inclusion criteria. Fifty-six patients (54.4%) were female. The current average age was 28.4±7.4years, while the age of epilepsy onset was 13.6±2.9years. Most patients corresponded to the subsyndrome of classic JME. Forty-six (44.7%) patients were free from all seizure types, and 76 (73.7%) patients were free from GTC seizures. No significant difference was found in seizure freedom among patients using a low dose of valproate versus a high dose (p=0.535) or among patients with low blood levels versus high blood levels (p=0.69). In patients with JME, it seems appropriate to use low doses of valproate (500mg to 1000mg) for initial treatment and then to determine if freedom from seizures was attained.

Chromosome loci vary by juvenile myoclonic epilepsy subsyndromes: linkage and haplotype analysis applied to epilepsy and EEG 3.5-6.0 Hz polyspike waves.

Juvenile myoclonic epilepsy (JME), the most common genetic epilepsy, remains enigmatic because it is considered one disease instead of several diseases. We ascertained three large multigenerational/multiplex JME pedigrees from Honduras with differing JME subsyndromes, including Childhood Absence Epilepsy evolving to JME (CAE/JME; pedigree 1), JME with adolescent onset pyknoleptic absence (JME/pA; pedigree 2), and classic JME (cJME; pedigree 3). All phenotypes were validated, including symptomatic persons with various epilepsies, asymptomatic persons with EEG 3.5-6.0 Hz polyspike waves, and asymptomatic persons with normal EEGs. Two-point parametric linkage analyses were performed with 5185 single-nucleotide polymorphisms on individual pedigrees and pooled pedigrees using four diagnostic models based on epilepsy/EEG diagnoses. Haplotype analyses of the entire genome were also performed for each individual. In pedigree 1, haplotyping identified a 34 cM region in 2q21.2-q31.1 cosegregating with all affected members, an area close to 2q14.3 identified by linkage (Z max = 1.77; pedigree 1). In pedigree 2, linkage and haplotyping identified a 44 cM cosegregating region in 13q13.3-q31.2 (Z max = 3.50 at 13q31.1; pooled pedigrees). In pedigree 3, haplotyping identified a 6 cM cosegregating region in 17q12. Possible cosegregation was also identified in 13q14.2 and 1q32 in pedigree 3, although this could not be definitively confirmed due to the presence of uninformative markers in key individuals. Differing chromosome regions identified in specific JME subsyndromes may contain separate JME disease-causing genes, favoring the concept of JME as several distinct diseases. Whole-exome sequencing will likely identify a CAE/JME gene in 2q21.2-2q31.1, a JME/pA gene in 13q13.3-q31.2, and a cJME gene in 17q12.

Functional connectivity changes related to cognitive and motor performance in spinocerebellar ataxia type 2.

BACKGROUND: Several neuropathological studies in spinocerebellar ataxia type 2 (SCA2) have revealed significant atrophy of the cerebellum, brainstem, sensorimotor cortex, and several regions in the frontal lobe. However, the impact of the neurodegeneration on the functional integration of the remaining tissue is unknown. To analyze the clinical impact of these functional changes, we correlated the abnormal functional connectivity found in SCA2 patients with their scores in clinical scales. To obtain the functional connectivity changes, we followed two approaches. In one we used areas with significant cerebellar gray matter atrophy as anchor seeds, and in the other we performed a whole-brain data-driven analysis. METHODS: Fourteen genetically confirmed SCA2 patients and aged-matched healthy controls participated in the study. Voxel-based morphometry and resting-state functional magnetic resonance imaging (fMRI) were done to analyze structural and functional brain changes. Independent component analysis and dual regression were used for intrinsic network comparison. Significant functional connectivity differences were correlated with the behavioral scores. RESULTS: Seed-based analysis found reduced functional connectivity within the cerebellum and between the cerebellum and frontal/parietal cortices. Cerebellar functional connectivity increases were found with parietal, frontal, and temporal areas. Intrinsic network analysis found a functional decrease in the cerebellar network, and increase in the default-mode and fronto-parietal networks. Further analysis showed significant correlations between clinical scores and the abnormal functional connectivity strength. CONCLUSION: Our findings show significant correlations between functional connectivity changes in key areas affected in SCA2 and these patients' motor and neuropsychological impairments, adding an important insight to our understanding of the pathophysiology of SCA2.

CYP2D6 genetic polymorphisms in Southern Mexican Mayan Lacandones and Mestizos from Chiapas.

AIM: In previous CYP2D6 genotyping studies in Mexican-Amerindians a very low frequency of poor metabolizers (PMs) has been reported. Moreover, ultrarapid metabolizers (UMs) status has only been analyzed in some groups from Northern Mexico. MATERIALS & METHODS: In the present study we evaluated the hypothesis of low frequency of PMs in Mexican-Amerindians in Southern Mexican populations from Chiapas (Lacandones [ML] vs Mestizos [MM]). The frequency of UMs is also reported. CYP2D6 alleles *2, *3, *4, *5, *6, *10, *17, *35 and *41 and copy number variations were analyzed in 154 ML and 100 MM healthy volunteers. RESULTS: The PM frequency was 0% in MLs and 1% in MMs, and for UMs was 2.6% in MLs and 3% in MMs. CONCLUSION: The present data support previous findings reporting a very low frequency of CYP2D6 PMs in Mexican-Amerindians. Furthermore, the predicted UM phenotype in both MMs and MLs was lower than those reported for most Mexican populations.

Late onset Lafora disease and novel EPM2A mutations: breaking paradigms.

Lafora disease (LD) is an autosomal recessive progressive myoclonus epilepsy with classic adolescent onset of stimuli sensitive seizures. Patients typically deteriorate rapidly with dementia, ataxia, vegetative failure and death by 25 years of age. LD is caused by homozygous mutations in EPM2A or EPM2B genes. We found four novel mutations in EPM2A - three in exon 4 (Q247X, H265R G279C) and one in exon 1 (Y86D) - and a previously described mutation in exon 4 (R241X). These five EPM2A mutations were found in four index cases and affected relatives. Patient 1 with classic LD was doubly heterozygous for H265R and R241X in exon 4; while Patient 2, who also had classic LD, was homozygous for Q247X in exon 4. Patient 3 with classic LD was homozygous for Y86D in exon 1, but the same mutation in his affected brother manifested an atypical earlier childhood onset. For the first time, we describe a later onset and slower progression of EPM2A-deficient LD seen in Patient 4 and her three sisters who were doubly heterozygous for R241X and G279C in exon 4. In these sisters, seizures started later at 21 to 28 years of age and progressed slowly with patients living beyond 30 years of age. Our observations suggest that variations in phenotypes of EPM2A-deficient LD, like an earlier childhood or adolescent or later adult onset with a rapid or slower course, depend on a second modifying factor separate from pathogenicity or exon location of EPM2A mutations. A modifying gene amongst the patient's genetic background or environmental factors may condition age of onset and rapid or slow progression of LD.

Repeat interruptions in spinocerebellar ataxia type 10 expansions are strongly associated with epileptic seizures.

Spinocerebellar ataxia type 10 (SCA10), an autosomal dominant neurodegenerative disorder, is the result of a non-coding, pentanucleotide repeat expansion within intron 9 of the Ataxin 10 gene. SCA10 patients present with pure cerebellar ataxia; yet, some families also have a high incidence of epilepsy. SCA10 expansions containing penta- and heptanucleotide interruption motifs, termed "ATCCT interruptions," experience large contractions during germline transmission, particularly in paternal lineages. At the same time, these alleles confer an earlier age at onset which contradicts traditional rules of genetic anticipation in repeat expansions. Previously, ATCCT interruptions have been associated with a higher prevalence of epileptic seizures in one Mexican-American SCA10 family. In a large cohort of SCA10 families, we analyzed whether ATCCT interruptions confer a greater risk for developing seizures in these families. Notably, we find that the presence of repeat interruptions within the SCA10 expansion confers a 6.3-fold increase in the risk of an SCA10 patient developing epilepsy (6.2-fold when considering patients of Mexican ancestry only) and a 13.7-fold increase in having a positive family history of epilepsy (10.5-fold when considering patients of Mexican ancestry only). We conclude that the presence of repeat interruptions in SCA10 repeat expansion indicates a significant risk for the epilepsy phenotype and should be considered during genetic counseling.

Disruption of visual and motor connectivity in spinocerebellar ataxia type 7.

Spinocerebellar ataxia type 7 (SCA7) is an autosomal-dominant neurodegenerative disorder characterized by progressive ataxia and retinal dystrophy. It is caused by a CAG trinucleotide expansion in the ataxin7 gene. Anatomical studies have shown severe cerebellar degeneration and region-specific neocortical atrophy in SCA7 patients. However, the impact of the neurodegeneration on the functional integration of the remaining tissue is still unknown. The aim of this study was to examine functional connectivity abnormalities in areas with significant gray matter atrophy in SCA7 patients and their relationship with number of CAG repeats. Using a combination of voxel-based morphometry and resting-state fMRI, we studied 26 genetically confirmed SCA7 patients and aged-matched healthy controls. In SCA7 patients we found reduced functional interaction between the cerebellum and the middle and superior frontal gyri, disrupted functional connectivity between the visual and motor cortices, and increased functional coordination between atrophied areas of the cerebellum and a range of visual cortical areas compared with healthy controls. The degree of mutation expansion showed a negative effect on both the functional interaction between the right anterior cerebellum and the left superior frontal gyrus and the connectivity between the right anterior cerebellum and left parahippocampal gyrus. We found abnormal functional connectivity patterns, including both hypo- and hyperconnectivity, compared with controls. These abnormal patterns show reasonable association with the severity of gene mutation. Our findings suggest that aberrant changes are prevalent in both motor and visual systems, adding significantly to our understanding of the pathophysiology of SCA7.

Paradoxical effects of repeat interruptions on spinocerebellar ataxia type 10 expansions and repeat instability.

Spinocerebellar ataxia type 10 (SCA10) is an autosomal dominant neurodegenerative disorder caused by a noncoding ATTCT pentanucleotide expansion. An inverse correlation between SCA10 expansion size and age at onset has been reported, and genetic anticipation has been documented. Interruptions in the ATTCT expansion are known to occur within the expansion. In order to determine the effect of repeat interruptions in SCA10 expansions, we designed a PCR assay to easily identify ATCCT repeat interruptions in the 5'-end of the expansion. We screened a cohort of 31 SCA10 families of Mexican, Brazilian and Argentinean ancestry to identify those with ATCCT repeat interruptions within their SCA10 expansions. We then studied the effects of ATCCT interruptions on intergenerational repeat instability, anticipation and age at onset. We find that the SCA10 expansion size is larger in SCA10 patients with an interrupted allele, but there is no difference in the age at onset compared with those expansions without detectable interruptions. An inverse correlation between the expansion size and the age at onset was found only with SCA10 alleles without interruptions. Interrupted expansion alleles show anticipation but are accompanied by a paradoxical contraction in intergenerational repeat size. In conclusion, we find that SCA10 expansions with ATCCT interruptions dramatically differ from SCA10 expansions without detectable ATCCT interruptions in repeat-size-instability dynamics and pathogenicity.