Neuropsychological profile of a Filipino gentleman with X-linked dystonia-parkinsonism: a case report of Lubag disease

Neurocognitive profile of patients with X-linked dystonia-parkinsonism

X-linked dystonia-parkinsonism (XDP) is a debilitating movement disorder endemic to the Panay Island, Philippines. Most studies focus on motor symptoms, hence we reviewed the neurocognitive profile of XDP patients. Neurocognitive testing of XDP patients focused on five domains: general intellectual functioning, episodic memory, language, attention and executive function, and affect. Twenty-nine genetically confirmed patients were included. Twenty-six (89.6%) had impairments in one or more domains, while only three had no impairment in any domain. Attention and executive function was the most commonly affected domain (n = 23, 79.3%). Deficits in general intellect, episodic memory, attention and executive function and affect were seen in our subset of XDP patients. The striatal pathology affecting the frontostriatal circuitry mandating these cognitive processes is mainly implicated in these impairments. The results of our study provided further evidence on the extent of cognitive impairment in XDP using a select battery of neurocognitive tests.

Translation, Cultural Adaptation, and Validation of the Hiligaynon Montreal Cognitive Assessment Tool (MoCA-Hil) Among Patients With X-Linked Dystonia Parkinsonism (XDP)

Background: X-linked dystonia parkinsonism (XDP) is a neurodegenerative disease endemic to Filipinos with maternal lineage from Panay Island, Philippines. Patients present with dystonia concurrent with or followed by parkinsonism. Non-motor symptoms also predominate, affecting behavior and cognition. We aimed to translate and do cross-cultural adaptation and validation of the Montreal Cognitive Assessment Tool (MoCA) into Hiligaynon (MoCA-Hil), the language spoken in Panay Island, to perform baseline cognitive screening of XDP patients.

Methods: Forward translation to Hiligaynon was done by two translators, then back translation of a single version was adapted and approved by a committee. A pilot testing was done yielding the final translated version, which was then tested on 46 XDP patients. The test-retest reliability was measured for 11 patients. The XDP-MDSP (Movement Disorder Society of the Philippines) rating scale was used to assess disease severity.

Results: The MoCA-Hil showed an acceptable test-retest reliability [intraclass correlation (ICC) 0.74] and internal consistency (Cronbach's alpha 0.86 at baseline, 0.81 at 12 weeks). The two subscales with low ICC at 0.09 and 0.21 were delayed recall and orientation, respectively.

Conclusion: Translation, cultural adaptation and validation of the MoCA to Hiligaynon was successfully done. This tool may now be used in clinical practice and in research for Hiligaynon-speaking subjects.

X-Linked Dystonia-Parkinsonism: recent advances

PURPOSE OF REVIEW

Our understanding of X-Linked Dystonia-Parkinsonism (XDP) has advanced considerably in recent years because of a wealth of new data describing its genetic basis, cellular phenotypes, neuroimaging features, and response to deep brain stimulation (DBS). This review provides a concise summary of these studies.

RECENT FINDINGS

XDP is associated with a SINE-VNTR-Alu (SVA)-type retrotransposon insertion within the TAF1 gene. This element includes a hexameric DNA repeat expansion, (CCCTCT)n, the length of which varies among patients and is inversely correlated to age of disease onset. In cell models, the SVA alters TAF1 splicing and reduces levels of full-length transcript. Neuroimaging data have confirmed previous neuropathology studies that XDP involves a progressive striatal atrophy, while further detecting functional alterations in additional brain regions. In patients exhibiting features of both dystonia and parkinsonism, pallidal DBS has resulted in rapid improvement of hyperkinetic movements, but effects on hypokinetic features have been inconsistent.

SUMMARY

The discovery that XDP is linked to a polymorphic hexameric sequence suggests that it could share mechanisms with other DNA repeat disorders, whereas the transcriptional defect in cell models raises the possibility that strategies to correct TAF1 splicing could provide therapeutic benefit.

Clinicopathological Phenotype and Genetics of X-Linked Dystonia-Parkinsonism (XDP; DYT3; Lubag)

X-linked dystonia–parkinsonism (XDP; OMIM314250), also referred to as DYT3 dystonia or “Lubag” disease, was first described as an endemic disease in the Philippine island of Panay. XDP is an adult-onset movement disorder characterized by progressive and severe dystonia followed by overt parkinsonism in the later years of life. Among the primary monogenic dystonias, XDP has been identified as a transcriptional dysregulation syndrome with impaired expression of the TAF1 (TATA box-binding protein associated factor 1) gene, which is a critical component of the cellular transcription machinery. The major neuropathology of XDP is progressive neuronal loss in the neostriatum (i.e., the caudate nucleus and putamen). XDP may be used as a human disease model to elucidate the pathomechanisms by which striatal neurodegeneration leads to dystonia symptoms. In this article, we introduce recent advances in the understanding of the interplay between pathophysiology and genetics in XDP.

Nonmotor features in sex-linked dystonia parkinsonism

The natural history of sex-linked dystonia parkinsonism (XDP) has been well documented. However, its nonmotor features have not yet been fully described. We reviewed the available literature on the nonmotor features in XDP. We found five articles involving 79 XDP patients, three of which were on cognition and two on mood (anxiety and depression). There were two case reports showing executive dysfunction. The other paper showed impairments in abstract thinking and motor programming. Two articles were on mood (anxiety and depression). The prevalence of anxiety symptoms was 16.7% and 54.8-92.9% had depressive symptoms. The identification of these nonmotor features should lead to early and appropriate management.

Pre- and post- GPi DBS neuropsychological profiles in a case of X-linked dystonia-Parkinsonism

We present the pre to post bilateral globus pallidus interna (GPi) deep brain stimulation neuropsychological profiles of a 69-year-old patient with a 12-year history of X-linked dystonia-Parkinsonism (XDP). Pre-operative cognitive function was impaired in almost all domains and this impaired performance was not dependent on his medications. Following DBS, changes in neuropsychological functioning were examined using Reliable Change Indices and standardized z-score comparisons. Results showed reductions in processing speed in the context of stable performance in language and visuospatial domains. Post-operative improvements occurred on a cognitive screening measure, verbal memory, and a test of problem-solving skills. This is the first report on an individual with XDP who was cognitively impaired, but had good outcome following GPi bilateral stimulation to treat debilitating motor symptoms. The possible mechanisms for his stable cognitive performance include the target of his DBS, reduced medication dosage, and improvement in dystonia that may in turn have reduced patient's pain.

Differential response of dystonia and parkinsonism following globus pallidus internus deep brain stimulation in X-linked dystonia-parkinsonism (Lubag)

BACKGROUND

X-linked dystonia-parkinsonism (XDP; DYT3; Lubag) is an adult-onset hereditary progressive dystonia/parkinsonism which is typically minimally responsive to pharmacological treatment.

CASE REPORT

We report a 63- year-old man with a diagnosis of XDP who underwent bilateral globus pallidus internus deep brain stimulator (GPi-DBS) placement. His course initially began with right hand tremor and dystonia at age 57 and progressed to also include bradykinesia and rigidity. The patient tolerated the procedure without significant complications. GPi-DBS improved his right hand dystonia, but did not significantly improve his parkinsonism.

CONCLUSION

DBS may be a therapeutic option for select cases of XDP, but its specific indications must be carefully discussed, as the available cases have had mixed responses. Whether other targets may be more effective is not known.