Can rehabilitation improve the health and well-being in Friedreich's ataxia: a randomized controlled trial?

OBJECTIVE

To determine the effectiveness of a six-week rehabilitation programme followed by a home exercise programme for Friedreich's ataxia.

DESIGN

Randomized, delayed-start control single-blind trial.

SETTING

Outpatient rehabilitation centre.

SUBJECTS

Ambulant or non-ambulant individuals with Friedreich's ataxia.

INTERVENTION

Participants were randomized to a six-week outpatient rehabilitation programme, immediately (intervention group) or after a six-week delayed-start (control group). The rehabilitation was followed by a six-week home exercise programme.

MAIN MEASURES

The primary outcome was the Functional Independence Measure. Other measures included the Friedreich Ataxia Impact Scale and the Friedreich Ataxia Rating Scale. Outcomes were administered at baseline, 6, 12 and 18 weeks.

RESULTS

Of 159 individuals screened, 92 were excluded and 48 declined to participate. A total of 19 participants were enrolled in the study. There was no significant difference in Functional Independence Measure change from baseline to six weeks in the intervention group (mean ± standard deviation, 2.00 ± 3.16) as compared to the control group (0.56 ± 4.06). Change in the Friedreich Ataxia Impact Scale body movement subscale indicated a significant improvement in health and well-being in the intervention group compared to the control group ( P = 0.003). Significant within-group improvements in the Friedreich Ataxia Impact Scale and the motor domain of the Functional Independence Measure post-rehabilitation were not sustained post-home exercise programme.

CONCLUSION

Our study indicates that rehabilitation can improve health and well-being in individuals with Friedreich's ataxia; however, a larger study is required to have sufficient power to detect a significant change in the most sensitive measure of function, the motor domain of the Functional Independence Measure.

Measuring Inhibition and Cognitive Flexibility in Friedreich Ataxia

Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disorder with subtle impact on cognition. Inhibitory processes and cognitive flexibility were examined in FRDA by assessing the ability to suppress a predictable verbal response. We administered the Hayling Sentence Completion Test (HSCT), the Trail Making Test, and the Stroop Test to 43 individuals with FRDA and 42 gender- and age-matched control participants. There were no significant group differences in performance on the Stroop or Trail Making Test whereas significant impairment in cognitive flexibility including the ability to predict and inhibit a pre-potent response as measured in the HSCT was evident in individuals with FRDA. These deficits did not correlate with clinical characteristics of FRDA (age of disease onset, disease duration, number of guanine-adenine-adenine repeats on the shorter or larger FXN allele, or Friedreich Ataxia Rating Scale score), suggesting that such impairment may not be related to the disease process in a straightforward way. The observed specific impairment of inhibition and predictive capacity in individuals with FRDA on the HSCT task, in the absence of impairment in associated executive functions, supports cerebellar dysfunction in conjunction with disturbance to cortico-thalamo-cerebellar connectivity, perhaps via inability to access frontal areas necessary for successful task completion.

Cerebral compensation during motor function in Friedreich ataxia: The IMAGE-FRDA study

BACKGROUND

Friedreich ataxia is characterized by progressive motor incoordination that is linked to peripheral, spinal, and cerebellar neuropathology. Cerebral abnormalities are also reported in Friedreich ataxia, but their role in disease expression remains unclear.

METHODS

In this cross-sectional functional magnetic resonance imaging study, 25 individuals with Friedreich ataxia and 33 healthy controls performed simple (self-paced single-finger) and complex (visually cued multifinger) tapping tasks to respectively gauge basic and attentionally demanding motor behavior. For each task, whole brain functional activations were compared between groups and correlated with disease severity and offline measures of motor dexterity.

RESULTS

During simple finger tapping, cerebral hyperactivation in individuals with Friedreich ataxia at the lower end of clinical severity and cerebral hypoactivation in those more severely affected was observed in premotor/ventral attention brain regions, including the supplementary motor area and anterior insula. Greater activation in this network correlated with greater offline finger tapping precision. Complex, attentionally demanding finger tapping was also associated with cerebral hyperactivation, but in this case within dorsolateral prefrontal regions of the executive control network and superior parietal regions of the dorsal attention system. Greater offline motor precision was associated with less activation in the dorsal attention network.

DISCUSSION

Compensatory activity is evident in the cerebral cortex in individuals with Friedreich ataxia. Early compensation followed by later decline in premotor/ventral attention systems demonstrates capacity-limited neural reserve, while the additional engagement of higher order brain networks is indicative of compensatory task strategies. Network-level changes in cerebral brain function thus potentially serve to mitigate the impact of motor impairments in Friedreich ataxia. © 2017 International Parkinson and Movement Disorder Society.

Informed decision making and psychosocial outcomes in pregnant and nonpregnant women offered population fragile X carrier screening

PurposePopulation-based carrier screening for fragile X syndrome (FXS) is still not universally endorsed by professional organizations due to concerns around genetic counseling for complex information and potential for psychosocial harms.MethodsWe determined uptake levels, decision making, and psychosocial impact in a prospective study of pregnant and nonpregnant Australian women offered FXS carrier screening in clinical settings. Women received pretest genetic counseling, and completed questionnaires when deciding and one month later.ResultsOf 1,156 women recruited, 83.1% returned the first questionnaire with 70.6% nonpregnant and 58.8% pregnant women choosing testing (χ²=16.98, P<0.001). Overall, informed choice was high in both nonpregnant (77.4%) and pregnant (72.9%) women (χ²=0.21, P=0.644), and more tested (76.0%) than not-tested (66.7%) women (χ²=6.35, P=0.012) made an informed choice. Measures of depression, stress, and anxiety were similar to population norms for ~85% of women. Decisional conflict and regret were generally low; however, decisional uncertainty and regret were greater in pregnant than nonpregnant women, and not-tested than tested women (uncertainty: χ²=18.51, P<0.001 and χ²=43.11, P<0.001, respectively; regret: χ²=6.61, P<0.037 and χ²=35.54, P<0.001, respectively).ConclusionWe provide evidence to inform guidelines that population FXS carrier screening can be implemented with minimal psychosocial harms following appropriate information and prescreening genetic counseling.

Rehabilitation for Individuals With Genetic Degenerative Ataxia: A Systematic Review

BACKGROUND

Treatment of genetic degenerative ataxia is currently based on symptom management and maintenance of function. However, utilization of rehabilitation is limited due to a lack of evidence supporting its efficacy.

OBJECTIVE

This systematic review evaluated rehabilitation interventions for individuals with genetic degenerative ataxia. In addition, long-term outcomes from rehabilitation and optimal duration and intensity of rehabilitation were examined.

METHODS

A comprehensive search of 4 databases (MEDLINE, CINAHL, PEDro, and Cochrane) identified randomized, nonrandomized controlled, and cohort studies published from inception through to January 2016. The studies included at least one measure examining function, ataxia, balance, or gait. Methodological quality was assessed with the Australian National Health and Medical Research Council (NHMRC) Hierarchy of Evidence and the randomized controlled trials were rated according to the PEDro scale.

RESULTS

Seventeen studies met eligibility criteria. Five randomized controlled trials were included; however, the majority were classified as level III-3 and IV studies. Of 292 participants included, 148 had autosomal dominant ataxia, and 85 had autosomal recessive ataxia. Rehabilitation interventions included coordination and balance training, multifaceted inpatient rehabilitation, a cycling regime, balance exercises with technology assisted biofeedback, respiratory muscle training, and treadmill training. Two studies examined adjuncts to rehabilitation. Fifteen of the 17 studies demonstrated a statistically significant improvement in at least 1 outcome measuring ataxia, function, gait, or balance. Less than half of the studies included assessment of long-term outcomes and follow-up time frames varied considerably.

CONCLUSION

There is consistent evidence that rehabilitation improves function, mobility, ataxia, and balance in genetic degenerative ataxia.

Friedreich's ataxia induced pluripotent stem cell-derived cardiomyocytes display electrophysiological abnormalities and calcium handling deficiency

We sought to identify the impacts of Friedreich's ataxia (FRDA) on cardiomyocytes. FRDA is an autosomal recessive degenerative condition with neuronal and non-neuronal manifestations, the latter including progressive cardiomyopathy of the left ventricle, the leading cause of death in FRDA. Little is known about the cellular pathogenesis of FRDA in cardiomyocytes. Induced pluripotent stem cells (iPSCs) were derived from three FRDA individuals with characterized GAA repeats. The cells were differentiated into cardiomyocytes to assess phenotypes. FRDA iPSC- cardiomyocytes retained low levels of FRATAXIN (FXN) mRNA and protein. Electrophysiology revealed an increased variation of FRDA- cardiomyocyte beating rates which was prevented by addition of nifedipine, suggestive of a calcium handling deficiency. Finally, calcium imaging was performed and we identified small amplitude, diastolic and systolic calcium transients confirming a deficiency in calcium handling. We defined a robust FRDA cardiac-specific electrophysiological profile in patient-derived iPSCs which could be used for high throughput compound screening. This cell-specific signature will contribute to the identification and screening of novel treatments for this life-threatening disease.

Expanding the phenotypic spectrum associated with mutations of DYNC1H1

Autosomal dominant mutations of DYNC1H1 cause a range of neurogenetic diseases, including mental retardation with cortical malformations, hereditary spastic paraplegia and spinal muscular atrophy. Using SNP array, linkage analysis and next generation sequencing, we identified two families and one isolated proband sharing a known spinal muscular atrophy, lower extremity predominant (SMALED) causing mutation DYNC1H1 c.1792C>T, p.Arg598Cys, and another family harbouring a c.2327C>T, p.Pro776Leu mutation. Here, we present a detailed clinical and pathological examination of these patients, and show that patients with DYNC1H1 mutations may present with a phenotype mimicking a congenital myopathy. We also highlight features that increase the phenotypic overlap with BICD2, which causes SMALED2. Serial muscle biopsies were available for several patients, spanning from infancy and early childhood to middle age. These provide a unique insight into the developmental and pathological origins of SMALED, suggesting in utero denervation with reinnervation by surrounding intact motor neurons and segmental anterior horn cell deficits. We characterise biopsy features that may make diagnosis of this condition easier in the future.

Dysphagia in Friedreich Ataxia

The objective of the study was to comprehensively characterise dysphagia in Friedreich ataxia (FRDA) and identify predictors of penetration/aspiration during swallowing. We also investigated the psychosocial impact of dysphagia on individuals with FRDA. Sixty participants with FRDA were screened for dysphagia using a swallowing quality of life questionnaire (Swal-QOL) and case history. Individuals reporting dysphagia underwent a standardised oromotor assessment (Frenchay Dysarthria Assessment, 2, FDA-2) and videofluoroscopic study of swallowing (VFSS). Data were correlated with disease parameters (age at symptom onset, age at assessment, disease duration, FXN intron 1 GAA repeat sizes, and Friedreich Ataxia Rating Scale (FARS) score). Predictors of airway penetration/aspiration were explored using logistic regression analysis. Ninety-eight percent (59/60) of participants reported dysphagia, of whom 35 (58.3%) underwent FDA-2 assessment, and 38 (63.3%) underwent VFSS. Laryngeal, respiratory, and tongue dysfunction was observed on the FDA-2. A Penetration-Aspiration Scale score above 3 (deemed significant airway compromise based on non-clinical groups) was observed on at least one consistency in 13/38 (34.2%) participants. All of those who aspirated (10/38, 26.3%) did so silently, with no overt signs of airway entry such as reflexive cough. Significant correlations were observed between dysphagic symptoms and disease duration and severity. No reliable predictors of penetration or aspiration were identified. Oropharyngeal dysphagia is commonly present in individuals with FRDA and worsens with disease duration and severity. Individuals with FRDA are at risk of aspiration at any stage of the disease and should be reviewed regularly. Instrumental analysis remains the only reliable method to detect aspiration in this population. Dysphagia significantly affects the quality of life of individuals with FRDA.

HFE p.C282Y homozygosity predisposes to rapid serum ferritin rise after menopause: A genotype-stratified cohort study of hemochromatosis in Australian women

BACKGROUND AND AIM

Women who are homozygous for the p.C282Y mutation in the HFE gene are at much lower risk of iron overload-related disease than p.C282Y homozygous men, presumably because of the iron-depleting effects of menstruation and pregnancy. We used data from a population cohort study to model the impact of menstruation cessation at menopause on serum ferritin (SF) levels in female p.C282Y homozygotes, with p.C282Y/p.H63D simple or compound heterozygotes and those with neither p.C282Y nor p.H63D mutations (HFE wild types) as comparison groups.

METHODS

A sample of the Melbourne Collaborative Cohort Study was selected for the "HealthIron" study (n = 1438) including all HFE p.C282Y homozygotes plus a random sample stratified by HFE-genotype (p.C282Y and p.H63D). The relationship between the natural logarithm of SF and time since menopause was examined using linear mixed models incorporating spline smoothing.

RESULTS

For p.C282Y homozygotes, SF increased by a factor of 3.6 (95% CI (1.8, 7.0), P < 0.001) during the first 10 years postmenopause, after which SF continued to increase but at less than half the previous rate. In contrast, SF profiles for other HFE genotype groups increase more gradually and did not show a distinction between premenopausal and postmenopausal SF levels. Only p.C282Y homozygotes had predicted SF exceeding 200 μg/L postmenopause, but the projected SF did not increase the risk of iron overload-related disease.

CONCLUSIONS

These data provide the first documented evidence that physiological blood loss is a major factor in determining the marked gender difference in expression of p.C282Y homozygosity.

Targeted sequencing identifies 91 neurodevelopmental-disorder risk genes with autism and developmental-disability biases

Gene-disruptive mutations contribute to the biology of neurodevelopmental disorders (NDDs), but most of the related pathogenic genes are not known. We sequenced 208 candidate genes from >11,730 cases and >2,867 controls. We identified 91 genes, including 38 new NDD genes, with an excess of de novo mutations or private disruptive mutations in 5.7% of cases. Drosophila functional assays revealed a subset with increased involvement in NDDs. We identified 25 genes showing a bias for autism versus intellectual disability and highlighted a network associated with high-functioning autism (full-scale IQ >100). Clinical follow-up for NAA15, KMT5B, and ASH1L highlighted new syndromic and nonsyndromic forms of disease.

Mutations in DCC cause isolated agenesis of the corpus callosum with incomplete penetrance

Brain malformations involving the corpus callosum are common in children with developmental disabilities. We identified DCC mutations in four families and five sporadic individuals with isolated agenesis of the corpus callosum (ACC) without intellectual disability. DCC mutations result in variable dominant phenotypes with decreased penetrance, including mirror movements and ACC associated with a favorable developmental prognosis. Possible phenotypic modifiers include the type and location of mutation and the sex of the individual.

A Novel Mechanism for Human Cardiac Ankyrin-B Syndrome due to Reciprocal Chromosomal Translocation

BACKGROUND

Cardiac rhythm abnormalities are a leading cause of morbidity and mortality in developed countries. Loss-of-function variants in the ANK2 gene can cause a variety of cardiac rhythm abnormalities including sinus node dysfunction, atrial fibrillation and ventricular arrhythmias (called the "ankyrin-B syndrome"). ANK2 encodes ankyrin-B, a molecule critical for the membrane targeting of key cardiac ion channels, transporters, and signalling proteins.

METHODS AND RESULTS

Here, we describe a family with a reciprocal chromosomal translocation between chromosomes 4q25 and 9q26 that transects the ANK2 gene on chromosome 4 resulting in loss-of-function of ankyrin-B. Select family members with ankyrin-B haploinsufficiency due to the translocation displayed clinical features of ankyrin-B syndrome. Furthermore, evaluation of primary lymphoblasts from a carrier of the translocation showed altered levels of ankyrin-B as well as a reduced expression of downstream ankyrin-binding partners.

CONCLUSIONS

Thus, our data conclude that, similar to previously described ANK2 loss-of-function "point mutations", large chromosomal translocations resulting in ANK2 haploinsufficiency are sufficient to cause the human cardiac ankyrin-B syndrome. The unexpected ascertainment of ANK2 dysfunction via the discovery of a chromosomal translocation in this family, the determination of the familial phenotype, as well as the complexities in formulating screening and treatment strategies are discussed.

Heterozygous mutations in HSD17B4 cause juvenile peroxisomal D-bifunctional protein deficiency

Objective:

To determine the genetic cause of slowly progressive cerebellar ataxia, sensorineural deafness, and hypergonadotropic hypogonadism in 5 patients from 3 different families.

Methods:

The patients comprised 2 sib pairs and 1 sporadic patient. Clinical assessment included history, physical examination, and brain MRI. Linkage analysis was performed separately on the 2 sets of sib pairs using single nucleotide polymorphism microarrays, followed by analysis of the intersection of the regions. Exome sequencing was performed on 1 affected patient with variant filtering and prioritization undertaken using these intersected regions.

Results:

Using a combination of sequencing technologies, we identified compound heterozygous mutations in HSD17B4 in all 5 affected patients. In all 3 families, peroxisomal D-bifunctional protein (DBP) deficiency was caused by compound heterozygosity for 1 nonsense/deletion mutation and 1 missense mutation.

Conclusions:

We describe 5 patients with juvenile DBP deficiency from 3 different families, bringing the total number of reported patients to 14, from 8 families. This report broadens and consolidates the phenotype associated with juvenile DBP deficiency.

Predictive genetic testing for neurodegenerative conditions: how should conflicting interests within families be managed?

Predictive genetic testing for a neurodegenerative condition in one individual in a family may have implications for other family members, in that it can reveal their genetic status. Herein a complex clinical case is explored where the testing wish of one family member was in direct conflict to that of another. The son of a person at 50% risk of an autosomal dominant neurodegenerative condition requested testing to reveal his genetic status. The main reason for the request was if he had the familial mutation, he and his partner planned to utilise preimplantation genetic diagnosis to prevent his offspring having the condition. His at-risk parent was clear that if they found out they had the mutation, they would commit suicide. We assess the potential benefits and harms from acceding to or denying such a request and present an approach to balancing competing rights of individuals within families at risk of late-onset genetic conditions, where family members have irreconcilable differences with respect to predictive testing. We argue that while it may not be possible to completely avoid harm in these situations, it is important to consider the magnitude of risks, and make every effort to limit the potential for adverse outcomes.

How should hyperferritinaemia be investigated and managed?

Hyperferritinaemia is commonly found in clinical practice. In assessing the cause of hyperferritinaemia, it is important to identify if there is true iron overload or not as hyperferritinaemia may be seen in other conditions such as excess alcohol intake, inflammation and non-alcoholic fatty liver disease. Assessment of whether the serum ferritin level is elevated or not should take into account body mass index, gender and age. This review article provides an overview of the different causes of hyperferritinaemia, differentiating those due to iron overload from those not due to iron overload, and provides an algorithm for clinicians to use in clinical practice to carry out appropriate investigations and management.

Cerebral and cerebellar grey matter atrophy in Friedreich ataxia: the IMAGE-FRDA study

Friedreich ataxia (FRDA) is traditionally associated with neuropathology in the cerebellar dentate nucleus and spinal cord. Growing evidence also suggests involvement of the cerebral and cerebellar cortices, although reports of structural abnormalities remain mixed. This study assessed the structural integrity of cortical grey matter in FRDA, focussing on regions in which pathology may underlie the motor deficits characteristic of this disorder. T1-weighted anatomical magnetic resonance imaging scans were acquired from 31 individuals with FRDA and 37 healthy controls. Cortical thickness (FreeSurfer) and cortical volume (SPM-VBM) were measured in cerebral motor regions-of-interest (primary motor, dorsal and ventral premotor, and supplementary motor areas) alongside unconstrained exploratory analyses of the cerebral and cerebellar cortices. Correlations were assessed between cortical thickness/volume measures and each of disease severity, length of the causative genetic triplet-repeat expansion, and finger-tapping behavioural measures. Individuals with FRDA had significantly reduced cortical thickness, relative to controls, in the premotor and supplementary motor areas. Reduced cortical thickness and/or volume were also observed in the cuneus and precuneus, posterior aspects of the medial and lateral prefrontal cortices, insula, temporal poles, and cerebellar lobules V, VI, and VII. Measures of clinical severity, genetic abnormality, and motor dysfunction correlated with volume loss in the lateral cerebellar hemispheres. These results suggest that atrophy preferentially affects premotor relative to primary areas of the cortical motor system, and also extends to a range of non-motor brain regions. Furthermore, cortical thickness and cortical volume findings were largely divergent, suggesting that each is sensitive to different aspects of neuropathology in FRDA. Overall, this study supports a disease model involving neural aberrations within the cerebral and cerebellar cortices, beyond those traditionally associated with this disorder.

Comorbid Medical Conditions in Friedreich Ataxia: Association With Inflammatory Bowel Disease and Growth Hormone Deficiency

Friedreich ataxia is a progressive degenerative disease with neurologic and cardiac involvement. This study characterizes comorbid medical conditions in a large cohort of patients with Friedreich ataxia. Patient diagnoses were collected in a large natural history study of 641 subjects. Prevalence of diagnoses in the cohort with Friedreich ataxia was compared with prevalence in the population without Friedreich ataxia. Ten patients (1.6%) had inflammatory bowel disease, 3.5 times more common in this cohort of individuals with Friedreich ataxia than in the general population. Four subjects were growth hormone deficient, reflecting a prevalence in Friedreich ataxia that is 28 times greater than the general population. The present study identifies specific diagnoses not traditionally associated with Friedreich ataxia that are found at higher frequency in this disease. These associations could represent coincidence, shared genetic background, or potentially interactive disease mechanisms with Friedreich ataxia.

Progression of Friedreich ataxia: quantitative characterization over 5 years

OBJECTIVE

Friedreich ataxia (FRDA) is a progressive neurodegenerative disorder of adults and children. This study analyzed neurological outcomes and changes to identify predictors of progression and generate power calculations for clinical trials.

METHODS

Eight hundred and twelve subjects in a natural history study were evaluated annually across 12 sites using the Friedreich Ataxia Rating Scale (FARS), 9-Hole Peg Test, Timed 25-Foot Walk, visual acuity tests, self-reported surveys and disability scales. Cross-sectional outcomes were assessed from recent visits, and longitudinal changes were gaged over 5 years from baseline.

RESULTS

Cross-sectional outcomes correlated with measures of disease severity. Age, genetic severity (guanine-adenine-adenine [GAA] repeat length), and testing site predicted performance. Serial progression was relatively linear using FARS and composite measures of performance, while individual performance outcomes were nonlinear over time. Age strongly predicted change from baseline until removing the effects of baseline FARS scores, when GAA becomes a more important factor. Progression is fastest in younger subjects and subjects with longer GAA repeats. Improved coefficients of variation show that progression results are more reproducible over longer assessment durations.

INTERPRETATION

While age predicted progression speed in simple analyses and may provide an effective way to stratify cohorts, separating the effects of age and genetic severity is difficult. Controlling for baseline severity, GAA is the major determinant of progression rate in FRDA. Clinical trials will benefit from enrollment of younger subjects, and sample size requirements will shrink with longer assessment periods. These findings should prove useful in devising gene therapy trials in the near future.

Standardized Assessment of Hereditary Ataxia Patients in Clinical Studies

BACKGROUND

Hereditary ataxias are a heterogeneous group of degenerative diseases of the cerebellum, brainstem, and spinal cord. They may present with isolated ataxia or with additional symptoms going beyond cerebellar deficits. There are an increasing number of clinical studies with the goal to define the natural history of these disorders, develop biomarkers, and investigate therapeutic interventions. Especially, early and preclinical disease stages are currently of particular interest.

METHODS AND RESULTS

Evidence-based, we review standards for sampling and storage of biomaterials, clinical and neuropsychological assessment, as well as neurophysiology and neuroimaging and recommendations for standardized assessment of ataxia patients in multicenter studies.

CONCLUSIONS

DNA, RNA, serum, and, if possible, cerebrospinal fluid samples should be processed following established standards. Clinical assessment in ataxia studies must include use of a validated clinical ataxia scale. There are several validated clinical ataxia scales available. There are no instruments that were specifically designed for assessing neuropsychological and psychiatric symptoms in ataxia disorders. We provide a list of tests that may prove valuable. Quantitative performance tests have the potential to supplement clinical scales. They provide additional objective and quantitative information. Posturography and quantitative movement analysis-despite valid approaches-require standardization before implemented in multicenter studies. Standardization of neurophysiological tools, as required for multicenter interventional trials, is still lacking. Future multicenter neuroimaging studies in ataxias should implement quality assurance measures as defined by the ADNI or other consortia. MRI protocols should allow morphometric analyses.