DHDDS and NUS1: A Converging Pathway and Common Phenotype.

BACKGROUND: Variants in dehydrodolichol diphosphate synthetase (DHDDS) and nuclear undecaprenyl pyrophosphate synthase 1 (NUS1) cause a neurodevelopmental disorder, classically with prominent epilepsy. Recent reports suggest a complex movement disorder and an overlapping phenotype has been postulated due to their combined role in dolichol synthesis. CASES: We describe three patients with heterozygous variants in DHDDS and five with variants affecting NUS1. They bear a remarkably similar phenotype of a movement disorder dominated by multifocal myoclonus. Diagnostic clues include myoclonus exacerbated by action and facial involvement, and slowly progressive or stable, gait ataxia with disproportionately impaired tandem gait. Myoclonus is confirmed with neurophysiology, including EMG of facial muscles. LITERATURE REVIEW: Ninety-eight reports of heterozygous variants in DHDDS, NUS1 and chromosome 6q22.1 structural alterations spanning NUS1, confirm the convergent phenotype of hypotonia at birth, developmental delay, multifocal myoclonus, ataxia, dystonia and later parkinsonism with or without generalized epilepsy. Other features include periodic exacerbations, stereotypies, anxiety, and dysmorphisms. Although their gene products contribute to dolichol biosynthesis, a key step in N-glycosylation, transferrin isoform profiles are typically normal. Imaging is normal or non-specific. CONCLUSIONS: Recognition of their shared phenotype may expedite diagnosis through chromosomal microarray and by including DHDDS/NUS1 in movement disorder gene panels.

Challenges in managing late-stage Parkinson's disease: Practical approaches and pitfalls.

BACKGROUND: Parkinson's disease is a universally progressive neurodegenerative disease. People living with Parkinson's disease for many years face progression from early- to mid- to late-stage Parkinson's disease (LSPD). While levodopa-responsive, predominantly motor features constitute the majority of symptom burden in early-stage Parkinson's disease, the disability in LSPD is characterised mainly by non-motor symptoms, which may be poorly levodopa responsive. OBJECTIVE: The aim of this article is to discuss recognition of LSPD and suggest strategies that may assist patients with LSPD in the community. DISCUSSION: The milestones of frequent falls, cognitive dysfunction, hallucinations and the need for residential care signal LSPD and predict time to death. Treatment aims shift to focus on patient comfort and conscientious prevention of exacerbations. In this article, challenges such as autonomic dysregulation, pain, cognitive decline and psychosis are addressed. These authors advocate a holistic approach, including supporting not only the patient with LSPD but also their carers.

An approach to acute clinical deterioration in patients with late-stage Parkinson's disease.

BACKGROUND: Idiopathic Parkinson's disease is a slowly progressive neurodegenerative disease. In the absence of disease-modifying therapies, patients inevitably progress to late-stage disease, characterised by a shift towards increasing disability from predominantly non-motor symptoms, which may be poorly levodopa responsive. OBJECTIVE: The aim of this article is to provide general practitioners (GPs) with a practical approach to the diagnosis and management of acute clinical deterioration in patients with late-stage Parkinson's disease. The authors outline common causes for such change and an approach to their workup and management. DISCUSSION: With an ageing population, we are seeing an increased prevalence of Parkinson's disease at all stages. Neurologists, geriatricians and GPs alike should therefore be familiar with the syndrome of late-stage Parkinson's disease and be equipped with treatment strategies to address acute non-motor and motor deteriorations.

Possible EIF2AK2-Associated Stress-Related Neurological Decompensation with Combined Dystonia and Striatal Lesions.

BACKGROUND: Variants in EIF2AK2 have been recently associated with a spectrum of neurological disease encompassing isolated dystonia to fever-related neurological decompensation, movement disorders and leukodystrophy. CASE: A 32-year old patient presented with childhood-onset episodes of neurological decompensation after febrile illness, progressive anarthria, dystonia and spasticity. The T2/FLAIR MRI showed bilateral posterolateral putamen hyperintensities and white matter changes suggestive of leukodystrophy. Initial extensive metabolic workup and whole genome sequencing (WGS) was unremarkable. Re-analysis of the WGS data revealed a variant in exon 3 of the EIF2AK2 gene [(NM_001135651.3): c.92C > G (p.Pro31Arg)]. EIF2AK2-associated disorders should be incorporated into the differential diagnosis of the syndrome of fever-related neurological decompensation with movement disorders, especially in the presence of abnormal neuroimaging. LITERATURE REVIEW: Disease-causing variants in EIF2AK2 have been reported in 24 individuals from 16 families in the literature to date. Two broad phenotypes have been described, including: (1) childhood-onset generalized dystonia and a normal brain MRI; and (2) early childhood-onset developmental delay combined with movement disorders, spasticity, and seizures in some. Notably, 92% of these patients have neurological deterioration after febrile illness or other physiological stress. Hypomyelination or delayed myelination and thin corpus callosum are seen in most patients and lower medullary lessions are common. Basal ganglia lesions have been reported previously in one case. CONCLUSIONS: EIF2AK2-associated disorders should be incorporated into the differential diagnosis of the syndrome of fever-related neurological decompensation with movement disorders, especially in the presence of abnormal neuroimaging.

The initial diagnosis and management of Parkinson's disease.

BACKGROUND: Parkinson's disease is a common, progressive neurodegenerative disorder, the prevalence of which is on the rise. The diagnosis and management of Parkinson's disease is therefore likely to become increasingly frequent in general practice. OBJECTIVE: The aim of this article is to provide a practical overview for the general practitioner of the initial diagnosis and management of Parkinson's disease. DISCUSSION: Parkinson's disease is a multisystem disorder, and the way the diagnosis is delivered, as well as the early management, can have a lasting impact on the patient experience. In this article, the authors present their preferred approach to diagnosis and initial treatment, while highlighting common pitfalls and some useful simple strategies for communicating the diagnosis.

Favourable Outcome in a 33-Year-Old Female with Acute Haemorrhagic Leukoencephalitis.

BACKGROUND: Acute haemorrhagic leukoencephalitis (AHLE) is a rare and rapidly fatal disease of unknown aetiology. There is a paucity of literature on the presentation and management of this rare disease. CASE DESCRIPTION: We report the case of a 33-year-old female presenting with headache and left-sided apraxia. Imaging revealed a right-sided white matter lesion with extensive cytotoxic oedema. Pathology was suggestive of AHLE. She underwent an open excisional biopsy and was treated with high-dose corticosteroids. Three months since symptom onset she remains clinically well with resolving apraxia and radiological appearance. CONCLUSION: This case may represent a milder spectrum of AHLE, which responded favourably to corticosteroids.