Adult-Onset Ataxia with Neuropathy and White Matter Abnormalities Due to a Novel SAMD9L Variant

Variants in tumor suppressor genes and in genes encoding DNA repairing proteins are associated with syndromes conferring neurologic features and increased risk for malignancy. The best example for these conditions is ataxia-telangiectasia (AT). A more rare and recent disease is an ataxia-pancytopenia syndrome (ATXPC) associated with heterozygous gain-of-function variants in the tumor suppressor gene SAMD9L (MIM 159550). Here, we describe a patient with a complex cerebellar syndrome associated with a novel SAMD9L pathogenic variant.publishedVersio

Peripheral nerve function : metabolic features, clinical assessment, and heat shock protein 27

Peripheral neuropathy is a common complication among patients with diabetes mellitus, but whether peripheral neuropathy is present in individuals with impaired glucose tolerance (IGT) is debatable. In order to identify and diagnose peripheral neuropathy correctly, it is important to evaluate diagnostic tools that can be implemented in routine health care to assess both large and small nerve fibre function. There is currently limited knowledge about neuroprotective factors that could be useful for measuring peripheral nerve function in individuals at risk of developing neuropathy such as those with diabetes mellitus. Thus, studies are needed to investigate potential neuroprotective factors in relation to peripheral nerve function in humans. Objectives: The overall goal of this thesis was to study the metabolic features and clinical assessment of peripheral nerve function and the potential relationship between the neuroprotective factor heat shock protein 27 (HSP27) and peripheral nerve function. Methods: Thirty-nine participants with normal glucose tolerance (NGT) and 29 participants with IGT were recruited from the population-based Västerbotten Intervention Programme in 2003–2004. Patients with type 2 diabetes mellitus (T2DM, n = 51) were recruited from primary health care centres. NGT and IGT individuals underwent two separate oral glucose tolerance tests to verify their glucose status. The peripheral nerve function in the lower limb was assessed by nerve conduction studies, neuropathy disability scoring, quantitative sensory tests, and skin biopsies with subsequent quantification of intraepidermal nerve fibre density (IENFD). The concentrations of HSP27 in serum were determined in the NGT, IGT, and T2DM individuals. Patients with type 1 diabetes mellitus (T1DM) were recruited from the Diabetes Clinic, Skåne University Hospital in Malmö, Sweden (n = 27) in 1992 and were followed-up in 2005. Baseline and follow-up concentrations of HSP27 were determined in T1DM patients as well as in healthy non-diabetic controls (n = 397). The T1DM patients underwent nerve conduction studies and thermal and vibration perception threshold tests at baseline and at follow-up. Delta changes in HSP27 concentrations and small and large nerve fibre function were calculated. Results: There was no difference between IGT and NGT in sural nerve conduction, intraepidermal nerve fibre density, or thermal thresholds. The biothesiometer had a sensitivity of 82% and a specificity of 72% in identifying peripheral neuropathy with a cut-off value of ≥24.5 V at the medial malleolus. Adding the quantification of IENFD to the combination of the tuning fork and biothesiometer increased the diagnostic sensitivity from 81% to 95%, the negative predictive value from 87% to 94%, and the positive likelihood ratio from 1.8 to 1.9 when identifying small nerve fibre dysfunction. T2DM patients had lower HSP27 concentrations (mean HSP27 = 412 pg/mL, 95% CI 284–598 pg/mL) than NGT (mean HSP27 = 722 pg/mL, 95% CI 564–922 pg/mL) and IGT (mean HSP27 = 1010 pg/mL, 95% CI 638–1300 pg/mL) individuals (p <0.05 for both comparisons). T1DM patients had lower HSP27 concentrations at baseline (mean HSP27 = 547 pg/mL, 95% CI 421–711 pg/mL) and at follow-up (mean HSP27 = 538 pg/mL, 95% CI 417–693 pg/mL) compared to healthy controls (mean HSP27 = 785 pg/mL, 95% CI 732–842 pg/mL), p <0.05 for both comparisons). High concentrations of HSP27 were associated with better large nerve fibre function (Odds ratio = 2.51, 95% CI 1.25–5.05, p <0.05). Deteriorating large nerve fibre function correlated with decreasing HSP27 concentrations over time in T1DM patients (r = 0.50, p = 0.01). Conclusions: Measures of large and small nerve fibre function in IGT individuals do not differ significantly from NGT individuals. The existence of peripheral neuropathy as a consequence of IGT is not likely, and extensive control of neuropathy in IGT individuals is not advocated by this thesis. The biothesiometer is a useful clinical tool to identify peripheral neuropathy in routine health care. Quantification of IENFD using skin biopsies in combination with methods measuring vibrotactile sense, such as the biothesiometer and the tuning fork, increase the diagnostic usefulness of identifying small nerve fibre dysfunction. High HSP27 concentrations are associated with better peripheral large nerve fibre function. Patients with diabetes mellitus have lower HSP27 concentrations than healthy non-diabetic controls, and deterioration of large nerve fibre function correlates with a decrease in HSP27 concentrations over time in T1DM. This could be indicative of insufficient neuroprotection in patients with diabetes mellitus

Evaluation of clinical tools and their diagnostic use in distal symmetric polyneuropathy

Aims: To compare the diagnostic usefulness of tuning fork, monofilament, biothesiometer and skin biopsies in peripheral neuropathy in individuals with varying glucose metabolism. Methods: Normoglycaemic, impaired glucose tolerance (IGT) and type 2 diabetes (T2DM) individuals were recruited. Nerve conduction studies (NCS) and thermal threshold tests were performed. Vibrotactile sense was tested with a biothesiometer and a 128-Hz tuning fork. Touch/pressure perception was examined with a 10-g monofilament. Skin biopsies were performed and intraepidermal nerve fibres were quantified. Distal symmetric polyneuropathy (DSPN) was defined as neuropathy disability score >= 2 and abnormal NCS. Thermal threshold tests were used to define small nerve fibre neuropathy (sDSPN) in cases where NCS (large nerve fibres) were normal. Results: The prevalence of DSPN and sDSPN in the whole group (n = 119) was 18% and 23%, respectively. For the biothesiometer, a cut-off of >= 24.5V had a sensitivity of 82% and specificity of 70% (AUC = 0.81, 95% CI 0.71-0.91) when evaluating DSPN. An intraepidermal nerve fibre density cut-off of <= 3.39 fibres/mm showed a sensitivity of 74% and specificity of 70% in the detection of sDSPN, whereas the sensitivity of the tuning fork and the biothesiometer were relatively low, 46% and 67%, respectively. When combining skin biopsies with the tuning fork, 10 more sDSPN cases were identified. Adding skin biopsy to the combination of the tuning fork and biothesiometer increased the sensitivity of finding sDSPN cases, but not DSPN, from 81% to 93%. Conclusion: Using a biothesiometer in clinical routine might be a sensitive method to detect large nerve fibre dysfunction in the lower extremity, whereas skin biopsies in combination with methods measuring vibrotactile sense could increase the diagnostic sensitivity of detecting peripheral neuropathy at an early stage. (C) 2013 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved

No Difference in Small or Large Nerve Fiber Function Between Individuals With Normal Glucose Tolerance and Impaired Glucose Tolerance

OBJECTIVE-To assess small and large nerve fiber function in people with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS-Participants were recruited consecutively from a population-based cohort: NGT (n = 39), IGT (n = 29), and T2D (n = 51). Electrophysiological measures included nerve conduction studies and thermal thresholds. Intraepidermal nerve fiber density (IENFD) in skin biopsies was calculated. RESULTS-There was no difference between IGT and NGT in sural nerve conduction, IENFD, and thermal thresholds. IENFD was significantly lower in T2D (median = 2.8 fibers/mm [interquartile range 1.1-4.7 fibers/mm]) than NGT individuals (4.5 fibers/mm [3.4-6.1 fibers/mm]; P < 0.05). T2D participants had poorer nerve conduction and higher heat thresholds than NGT and IGT. CONCLUSIONS-Large and small nerve function in people with IGT did not differ from those with NGT. Our finding does not support the existence of neuropathy in a prediabetic stage. Diabetes Care 36:962-964, 201

Autonomic Neuropathy : a Prospective Cohort Study of Symptoms and E/I Ratio in Normal Glucose Tolerance, Impaired Glucose Tolerance, and Type 2 Diabetes

Background: Autonomic neuropathy in diabetes, in addition to causing a range of symptoms originating from the autonomic nervous system, may increase cardiovascular morbidity. Our aim was to study the progression of autonomic neuropathy, based on symptom score and evaluation of an autonomic test, in persons with normal and impaired glucose tolerance and in patients with type 2 diabetes (T2D). Methods: Participants were recruited in 2003/2004 with a follow-up in 2014. The participants' glucose tolerance was categorized using oral glucose tolerance tests. Symptoms were evaluated using an autonomic symptom score (ASS), ECG was used to test cardiac autonomic function based on the expiration/inspiration ratio (E/I ratio), and blood samples were taken on both occasions. Results: ASSs were higher at follow-up in the T2D patients than in the normal glucose tolerance group (mean 1.21 +/- 1.30 vs. 0.79 +/- 0.7; p &lt; 0.05). E/I ratio did not deteriorate more than could be expected as an aging effect in well-controlled T2D. No relationship was found between E/I ratio and HbA1c or ASS. Conclusion: The presence of autonomic symptoms increased over time in T2D patients, but the symptoms did not correlate with the Ell ratio in this metabolically well-controlled cohort. ASSs can be a useful clinical tool when assessing the progression of autonomic dysfunction in patients with abnormal glucose metabolism

Autonomic Neuropathy—a Prospective Cohort Study of Symptoms and E/I Ratio in Normal Glucose Tolerance, Impaired Glucose Tolerance, and Type 2 Diabetes

BackgroundAutonomic neuropathy in diabetes, in addition to causing a range of symptoms originating from the autonomic nervous system, may increase cardiovascular morbidity. Our aim was to study the progression of autonomic neuropathy, based on symptom score and evaluation of an autonomic test, in persons with normal and impaired glucose tolerance and in patients with type 2 diabetes (T2D).MethodsParticipants were recruited in 2003/2004 with a follow-up in 2014. The participants’ glucose tolerance was categorized using oral glucose tolerance tests. Symptoms were evaluated using an autonomic symptom score (ASS), ECG was used to test cardiac autonomic function based on the expiration/inspiration ratio (E/I ratio), and blood samples were taken on both occasions.ResultsASSs were higher at follow-up in the T2D patients than in the normal glucose tolerance group (mean 1.21 ± 1.30 vs. 0.79 ± 0.7; p &lt; 0.05). E/I ratio did not deteriorate more than could be expected as an aging effect in well-controlled T2D. No relationship was found between E/I ratio and HbA1c or ASS.ConclusionThe presence of autonomic symptoms increased over time in T2D patients, but the symptoms did not correlate with the E/I ratio in this metabolically well-controlled cohort. ASSs can be a useful clinical tool when assessing the progression of autonomic dysfunction in patients with abnormal glucose metabolism

Temporal trend of small nerve fibre degeneration in people with and without type 2 diabetes mellitus

Aims We investigated the long-term temporal trend of intraepidermal nerve fibre density (IENFD) and the association between changes in IENFD and metabolic factors in individuals with and without type 2 diabetes. Methods A total of 66 participants were enrolled in this longitudinal population-based study, at baseline consisting of 35 individuals (median 61 years) without diabetes and 31 individuals with type 2 diabetes mellitus. Participants underwent clinical and electrophysiological examinations, as well as a skin biopsy both at baseline and at the follow-up visit (mean 8.1 +/- 0.5 years). IENFD was assessed in thin sections of 5 mu m, stained with the protein gene product 9.5-antibody and compared between the groups. Results IENFD decreased during the period in both groups, with a greater decline in the group without diabetes than in type 2 diabetes (-2.3 and -0.6 fibres/mm respectively; p &amp;lt; 0.001). While IENFD at baseline was significantly reduced in type 2 diabetes relative to people without (p &amp;lt; 0.001), no difference in IENFD was found between groups at the follow-up (p = 0.183). Linear mixed model analysis indicated that age, weight and HbA(1c) were associated with decrease in IENFD in the total population (p &amp;lt; 0.007). IENFD also decreased with increasing age and weight, but not with HbA(1c), in the separate groups (p &amp;lt; 0.049). Conclusions Despite lower IENFD levels at baseline in type 2 diabetes, IENFD was equal between the groups at follow-up. A decrease in IENFD is to a limited extent affected by body weight, and HbA(1c), but age seems to be the long-term determinant of IENFD in an elderly population.Funding Agencies|Vasterbotten Lans Landsting; Umea Universitet; Skanes universitetssjukhus; Lunds Universitet; Diabetesforbundet</p

Table_5.PDF

Background<p>Autonomic neuropathy in diabetes, in addition to causing a range of symptoms originating from the autonomic nervous system, may increase cardiovascular morbidity. Our aim was to study the progression of autonomic neuropathy, based on symptom score and evaluation of an autonomic test, in persons with normal and impaired glucose tolerance and in patients with type 2 diabetes (T2D).</p>Methods<p>Participants were recruited in 2003/2004 with a follow-up in 2014. The participants’ glucose tolerance was categorized using oral glucose tolerance tests. Symptoms were evaluated using an autonomic symptom score (ASS), ECG was used to test cardiac autonomic function based on the expiration/inspiration ratio (E/I ratio), and blood samples were taken on both occasions.</p>Results<p>ASSs were higher at follow-up in the T2D patients than in the normal glucose tolerance group (mean 1.21 ± 1.30 vs. 0.79 ± 0.7; p < 0.05). E/I ratio did not deteriorate more than could be expected as an aging effect in well-controlled T2D. No relationship was found between E/I ratio and HbA1c or ASS.</p>Conclusion<p>The presence of autonomic symptoms increased over time in T2D patients, but the symptoms did not correlate with the E/I ratio in this metabolically well-controlled cohort. ASSs can be a useful clinical tool when assessing the progression of autonomic dysfunction in patients with abnormal glucose metabolism.</p