Affiliations: [a] Department of Neurology, Dayanand Medical College & Hospital, Civil Lines, Ludhiana, India
| [b] Genomics and Molecular Medicine, CSIR - Institute of Genomics and Integrative Biology, Delhi, India
| [c] Department of Neurology, Neuroscience Centre, All India Institute of Medical Sciences, New Delhi, India
| [d] Department of Neurology, Post Graduate Institute of Medical Education and Research, Dr. Ram Manohar Lohia Hospital, New Delhi, India
| [e] Departmentt of Neurology, Safdurjung Hospital, Delhi, India
| [f] Department of Neurology, GB Pant Hospital, Delhi, India
| [g] Department of Neurology, Institute of Human Behaviour and Allied Sciences, Delhi, India
Correspondence to: Dr. Mohammed Faruq, MBBS, PhD, Senior Scientist, Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Mall Road, New Delhi, India. Tel.: +91 11 27666156; Fax: +91 11 27667471; E-mails: [email protected] and [email protected].
Note:  These authors contributed equally to this work.
Abstract: Background:The diagnostic workup for choreiform movement disorders including Huntington’s disease (HD) and those mimicking HD like phenotype is complex. Objective:The aim of the present study was to genetically define HD and HD-like presentations in an Indian cohort. We also describe HTT-CAG expansion manifesting as neuroferritinopathy-like disorder in four families from Punjab in India. Materials and methods:159 patients clinically diagnosed as HD and HD-like presentations from various tertiary neurology clinics were referred to our centre (CSIR-IGIB) for genetic investigations. As a first tier test, CAG-TNR for HTT was performed and subsequently HD-negative samples were screened for JPH3 (HDL2), TBP (SCA17), ATN1 (DRPLA), PPP2R2B (SCA12) and GGGGCC expansion in C9orf72 gene. Four families presenting as neuroferritinopathy-like disorder were also investigated for HTT-CAG expansion. Results:94 of 159 (59%) patients were found to have expanded HTT-CAG repeats. Pathogenic repeat expansion in JPH3, TBP, ATN1 and C9orf72 were not found in HD negative cases. Two patients were positive for SCA12-CAG expansion in pathogenic length, whereas 5 cases harboured TBP-CAG repeats falling in reduced penetrance range of 41– 48 repeats for SCA17. Four unrelated families, presented with atypical chorea and brain MRI findings suggestive of basal ganglia abnormalities mimicking neuroferritinopathy were found to harbour HTT-CAG expansion. Conclusion:We present SCA12 as a new reported phenocopy of HD which should be considered for diagnostic workout along with SCA17 for HD-like syndromes. This study also illustrates the necessity, to consider evolving HD like phenotype, as a clinical diagnosis for cases with initial manifestations depicting neuroferritinopathy.