Massimo Marano

Niemann-Pick type C: focus on the adolescent/adult onset form.

Niemann–Pick disease type C (NP-C) is an inherited sphingolipidosis characterized by progressive neurological deterioration and early mortality. The symptomatology and disease progression of NP-C are markedly affected by the age at onset of neurological manifestations, and categorization into early-infantile, late-infantile, juvenile, adolescent/adult neurological onset forms can aid evaluation of disease course and responses to therapy. Here, we review current information on the detection, diagnosis, monitoring and treatment of NP-C, with a focus on the adolescent/adult-onset form. A recent analysis indicated that the combined incidence of NP-C related to NPC1 gene mutations (NPC1) and NP-C related to NPC2 gene mutations (NPC2) is approximately 1 case in every 89 000 live births. In particular, late-onset phenotypes might well provide a greater contribution to the overall incidence than has previously been reported. Some neuropathological features in NP-C are held in common with other advanced age-onset diseases such as Alzheimers disease. Visceral symptoms such as splenomegaly are frequently asymptomatic in patients with adolescent/adult-onset NP-C, and are only occasionally detected during routine ultrasound assessments. In contrast, most patients with adolescent/adult-onset exhibit some degree of slowly progressive, non-disease-specific movement disorders (e.g. cerebellar ataxia), and/or more pathognomonic neurological signs such as vertical supranuclear gaze palsy. An increasing number of adolescent/adult-onset cases have been reported following initial recognition of cognitive impairment and/or psychiatric signs. The recent development and implementation of new clinical screening tools (e.g. the NP-C suspicion index) and biomarkers (e.g. plasma oxysterols) should help identify patients who warrant further investigation and possible treatment.

Polyglutamine expansion affects huntingtin conformation in multiple Huntington’s disease models

Conformational changes in disease-associated or mutant proteins represent a key pathological aspect of Huntington’s disease (HD) and other protein misfolding diseases. Using immunoassays and biophysical approaches, we and others have recently reported that polyglutamine expansion in purified or recombinantly expressed huntingtin (HTT) proteins affects their conformational properties in a manner dependent on both polyglutamine repeat length and temperature but independent of HTT protein fragment length. These findings are consistent with the HD mutation affecting structural aspects of the amino-terminal region of the protein, and support the concept that modulating mutant HTT conformation might provide novel therapeutic and diagnostic opportunities. We now report that the same conformational TR-FRET based immunoassay detects polyglutamine- and temperature-dependent changes on the endogenously expressed HTT protein in peripheral tissues and post-mortem HD brain tissue, as well as in tissues from HD animal models. We also find that these temperature- and polyglutamine-dependent conformational changes are sensitive to bona-fide phosphorylation on S13 and S16 within the N17 domain of HTT. These findings provide key clinical and preclinical relevance to the conformational immunoassay, and provide supportive evidence for its application in the development of therapeutics aimed at correcting the conformation of polyglutamine-expanded proteins as well as the pharmacodynamics readouts to monitor their efficacy in preclinical models and in HD patients.

Dyskinesias during levodopa–carbidopa intestinal gel (LCIG) infusion: Management inclinical practice

The continuous levodopaecarbidopa intestinal gel (LCIG) infusion is a valid alternative for motor control in advanced Parkinsons disease (PD). It has been demonstrated to improve motor fluctuation with a global increase in ON-time, generally without the outbreak of troublesome hyperkinesias [1]. However both peakdose and biphasic dyskinesias are observed in patients undergoing LCIG treatment. Here is reported our experience with a PD patient, whose LCIG treatment was challenged by the outbreak of peculiar dyskinesiasfollowingthe PEG-J-tube bedtime flushing. A 73 yearsold woman was affected by advanced PD with motor fluctuations. Because of her extreme susceptibility to develop dyskinesias even with very small doses of levodopa (otherwise defined as “brittle response” [2]), the maximum acceptable oral treatment was of 475 mg fractionated in 9 small doses a day. APEG-J was inserted and LCIG therapy was started in order to obtain a lower and more stable therapeutic regimen. A significant reduction of the OFFperiods and of the dyskinesias were obtained through a LCIG titration of the morning dose to1.5 ml (30 mg of levodopa), of the continuous dose to 1.0 ml (20 mg) per hour per 16 h a day (total dose of 350mg) and of the extra-doses to 1.0 ml (20mg). Nevertheless, at the end of the daily treatment, the mandatory operation of flushing the PEG-J-tube after pump disconnection [3] resulted in stereotypical violent peak-dose choreo-dystonic hyperkinesias that required patient protections to prevent disastrous falls. The tube cleaning led to the immediate delivery of the 3 ml (60 mg) of levodopa-gel contained in the device. Unfortunately the patient was highly sensitive to levodopa; so much that extra-doses have to be set at 1 ml (20mg) per dose. LCIG pump turning off may result in biphasic dyskinesias due to the incipient discontinuation of the levodopa effect; in this case the simple interruption of the infusion did not lead to any dyskinesia contrary to what was observed after bedtime tube cleaning. In fact through the flushing the patient received extra 60 mg of levodopa gel, that is three times the dose needed to overcome OFF-period, resulting in violent peak-dose dyskinesias. Levodopa gel is contained in a reservoir bag inside a hard plastic cassette. A used reservoir bag was cleaned out from residual gel through a solution of diluted ethyl alcohol delivered through a syringe connected to the cassette tube, and later rinsed with room temperature tap water. Then, the cassette was connected to the tube and the water was administered at usual maintenance dose (1 ml/h), so that it could slowly push the column of levodopa gel contained in the tube. After 3 h, water completely replaced the gel in the tube, and cleaning operations could be easily performed without the risk of delivering a high bolus of levodopa

Biological and clinical manifestations of juvenile Huntington's disease: a retrospective analysis

BACKGROUND Huntingtons disease is a rare, neurodegenerative disease caused by an expanded CAG repeat mutation in the huntingtin gene. Compared with adult-onset Huntingtons disease, juvenile Huntingtons disease (onset ≤20 years) is even rarer and has not been studied extensively. We aimed to further characterise juvenile Huntingtons disease by examining the effect of CAG repeat size on disease presentation, progression, and survival. METHODS We did a retrospective analysis of patients with juvenile Huntingtons disease aged 20 years or younger, according to the length of their CAG repeat and who had disabling psychiatric symptoms (with motor symptoms) or motor symptoms alone, and of patients with adult-onset Huntingtons disease manifesting aged 30-60 years with 40 or more CAG repeats, from the REGISTRY and ENROLL-HD platforms and from two institutional databases (Lega Italiana Ricerca Huntington Foundation and the Instituto Neurociencias de Buenos Aires and the Sanatorio de la Trinidad Mitre). Patients with psychiatric but no motor symptoms were excluded. We compared symptoms at onset and longitudinally in patients with juvenile Huntingtons disease with highly expanded (HE subgroup) or low expansion (LE subgroup) mutations, grouped by hierarchical clustering analysis. We also compared disease progression (longitudinal change in Unified Huntingtons Disease Rating Scale-Total Motor Score) and survival of patients with juvenile and adult-onset Huntingtons disease. FINDINGS We extracted medical records from 580 patients entered into the studies or databases between June 23, 2004, and March 31, 2018, of whom 36 patients met our definition of juvenile Huntingtons disease and 197 for adult-onset Huntingtons disease. According to caregiver reports, gait disturbance was more often a first presenting symptom in the HE subgroup (eight [80%] of 10 patients) than in the LE subgroup (seven [27%] of 26 patients; p=0·0071), whereas loss of hand dexterity was more common in the LE subgroup (11 [42%] of 26 patients) than in the HE subgroup (0 [0%] of 10 patients; p=0·0160). Compared with the LE subgroup, development delay (0 [0%] in the LE subgroup vs nine [90%] in the HE subgroup; p<0·0001), severe gait impairment (nine [35%] in the LE subgroup vs nine [90%] in the HE subgroup; p=0·0072), and seizures (three [11%] in the LE subgroup vs eight [80%] in the HE subgroup; p<0·0001) prevailed over time in the HE subgroup. Disease progression was more rapid in juvenile Huntingtons disease (n=14) than in adult-onset Huntingtons disease (n=52; generalised estimating equation model, p=0·0003). Of 121 deceased patients, median survival was shorter in the juvenile Huntingtons disease (n=17) cohort than in adult-onset Huntingtons disease (n=104) cohort (hazard ratio 2·18 [95% CI 1·08-4·40]; p=0·002). INTERPRETATION Patients with HE juvenile Huntingtons disease differ clinically from patients with LE juvenile Huntingtons disease or adult-onset Huntingtons disease, suggesting reclassification of this particularly aggressive form of Huntingtons disease might be required. FUNDING Lega Italiana Ricerca Huntington Foundation and IRCCS Ospedale Casa Sollievo della Sofferenza.

Resting‐state connectivity and modulated somatomotor and default‐mode networks in Huntington disease

To analyze brain functional connectivity in the somatomotor and default‐mode networks (DMNs) of patients with Huntington disease (HD), its relationship with gray matter (GM) volume loss, and functional changes after pridopidine treatment.

Teaching Video NeuroImages: Running into a “useless” hand

A 68-year-old woman presented with an insidious onset of strictly asymmetric left arm clumsiness (video at Neurology.org) in absence of any brain lesion but mild right hemisphere hypotrophy (figure). The presence of limb apraxia and bradykinesia fostered the clinical diagnosis of possible corticobasal syndrome, in the context of suspected corticobasal degeneration.1 Bradykinesia and apraxia are 2 possible different faces of hypokinesia; their correct discrimination is not a diagnostic problem if a higher-level disturbance of praxis is present. An isolated limb apraxia is a confounder, and its early recognition allows clinicians to suspect parkinsonism with apraxia as a prominent feature.2

Children with Mild CAG Repeat Expansion in HTT Gene Showing Psychiatric but not Neurological Presentation: Is It One More Shade of Huntington Disease?

Objective: Huntington disease (HD) generally manifests in adulthood. Large mutations with CAG repeat expansion in HTT gene may rarely cause juvenile Huntington disease (JHD) in early childhood or adolescence with atypical clinical features, i.e., atypical parkinsonism, if compared to adult patients. Our objective is to characterize the rare occurrence of clinical manifestations in children carrying mutations in the low-mild size, generally causing adult HD with typical choreic movements. Methods: We are following up a subgroup of young subjects with HD mutation who manifested with disabling psychiatric condition since early childhood or adolescence. We are collecting data by the observational studies Registry and ENROLL-HD since 2004. Among 60 JHD patients we are currently following-up, we selected people who carry a mutation in the mild range of CAG expansions (i.e., expected to manifest in adulthood), psychiatric manifestations and no neurological signs or movement disorders suggestive of HD. All patients were genetically (i.e., CAG size analysis) and clinically (i.e., total motor score within the Unified HD Rating Scale) characterized. Results: We found four subjects who showed the characteristics for this analysis. All four subjects presented a CAG expansion size <45 repeats. Two patients manifested a schizophrenia-like disturbance during their adolescence, with the later appearance of motor signs after age 20. In the other two cases, patients presented symptoms of autistic spectrum disorder, since infancy. One of them showed also a schizophrenia-like disturbance and, later, HD onset with motor signs after 20. A 45 year old patient is currently manifesting an autistic disorder in absence of others neurological signs. Conclusion: The description of JHD includes sometimes children with psychiatric manifestations associated with adult motor onset. We advise to pay careful attention to such rare conditions that might represent either psychiatric conditions erroneously classified as JHD or prodromic adult HD cases.

The Clinical Course of a Drug-induced Acute Dystonic Reaction in the Emergency Room

Background Acute dystonic reactions following the administration of safe, reliable drugs can occur and must be promptly recognized and treated in the emergency room. Phenomenology Shown The entire clinical course of an acute dystonic reaction due to metoclopramide, from early motor signs to full-blown clinical symptoms and resolution. Educational Value Providing elements for early recognition of a drug-induced movement disorder phenomenology.

C2 Induced pluripotent stem cells (IPSC) as a model of huntington’s disease

Background and rationale Huntington’s disease (HD) patients’ cell lines may theoretically offer the opportunity to study longitudinal changes due to the mutated protein in its own physiological context. We are therefore exploring whether human induced pluripotent stem cells (iPSCs) from HD subjects represent a model to investigate the polyQ effects in vitro. Aims 1) Creation of an iPS collection from HD subjects; 2) Analysis of neural functions in reprogrammed cell lines, according to the different repeat sizes. Methods Patient’s skin fibroblasts were reprogrammed into iPSCs introducing four pluripotency episomal factors (SOX2, KLF4, c-MYC AND OCT4) by virus-free protocol. All iPS clones that show an uniform flat morphology were characterised for their stemness and pluripotency, both in vitro through embryoid bodies formation and in vivo through teratoma formation assay. A new protocol was optimised for differentiation of iPCs derived embryoid bodies expressing all the three germ layers (ectoderm, mesoderm and endoderm) in neurospheres of Neuronal Precursor Cells (NPCs) (Vescovi et al., 1999). We may obtain a neural population of astrocytes, oligodendrocytes and neuron cells by spontaneous differentiation of neurospheres in particular conditions. Results We have now obtained skin biopsies from 20 mutation positive subjects (from pre- to advanced HD stages) and five controls, at IRCCS Casa Sollievo della Sofferenza, Mendel Institute of Human Genetics, based in Rome. As first step, we got samples from subjects carrying borderline (ie 36–40 CAG) and very high (over 60) repeats. Conclusion We expect this model will allow us to highlight polyQ dependent changes in neural function and differentiation, in vitro.

D13 Modulation of resting state brain connectivity highlights potentiality for functional mri biomarkers

Background The spatial pattern of atrophy of a disease is related to its functional connectivity structure, mapped by resting-state functional magnetic resonance imaging (fMRI). Increased somatomotor and default mode resting-state networks play key roles in Huntington’s disease pathophysiology. Objectives To analyse brain functional connectivity in the somatomotor and default mode networks in patients with different Huntington’s disease stages and HTT gene mutation sizes, its relationship with grey matter volume loss, and functional changes after pridopidine treatment. Methods Ten patients and 10 controls without treatment underwent T1-weighted imaging and resting-state fMRI; four patients were also assessed after 3 months of pridopidine treatment (90 mg/day). The seed-based functional connectivity patterns from the posterior cingulate cortex and the supplementary motor area (SMA), considered cortical hubs of the somatomotor and default mode networks, respectively, were computed. Grey matter volume was measured by FSL voxel-based morphometry. Results There was decreased grey matter volume in all cortical and subcortical areas involved in the somatomotor network in patients, with preservation of the SMA. Increased somatomotor and default mode network connectivity was seen in patients compared with controls. The volume of the SMA may be dependent on its connectivity. Pridopidine reduced the intensity of these aberrant connexions. Conclusions Abnormal functional connectivity of the somatomotor and default mode networks was observed in patients with Huntington’s disease, independent of brain atrophy, which may represent a marker of early dysfunction. Pridopidine modulates these netwoks by reducing connectivity. Results suggest that network connectivity may be used to measure response to experimental therapies.