Annals of Case Reports and Clinical Studies (ISSN: 2834-5673) | Volume 5, Issue 6 | Case Report | Open Access DOI
Shaun Nevil*
Shaun Nevil1*, Amay Wattamwar2, Pratyusha Dutta3, Shreya Gupta4, Kanishka Verma5, Vishvas Ramala GK6, Anton Charles S1 and Chaitra CS7
1Department of Internal Medicine, ESIC Medical College PGIMSR & Model Hospital, India
2Sri Siddhartha Medical College, Karnataka, India
3Assam Medical College and Hospital, Assam, India
4Lady Hardinge Medical College, New Delhi, India
5Sri Guru Ram Das Institute of Medical Sciences and Research, Punjab, India
6Mamata Medical College, Telangana, India
7Assistant Professor, Department of Internal Medicine, ESIC Medical College PGIMSR & Model Hospital, India
*Correspondence to: Shaun Nevil
Fulltext PDFHuntington Disease (HD) is an autosomal dominant neurodegenerative disorder caused by CAG repeat expansion in the HTT gene. Juvenile Huntington disease (JHD), defined by onset before 20 years, is uncommon and often differs from adult-onset disease, with cognitive, behavioural, rigidity, ataxia, and epileptic manifestations predominating over chorea. We report a 12-year-old girl presenting with a three-month history of mild bilateral action tremor and a two-month history of declining academic performance, accompanied by irritability and social withdrawal. Neurological examination revealed mild choreiform finger movements, axial hypotonia, subtle saccadic slowing, impaired tandem gait, and mild dysarthria. The Unified Huntington's Disease Rating Scale motor score was 18, while cognitive screening demonstrated deficits in attention and executive function. Genetic testing confirmed a pathogenic HTT CAG expansion of 62 repeats, with 18 repeats on the normal allele, establishing JHD. There was no known family history of HD. Cascade testing of the clinically asymptomatic 54-year-old mother unexpectedly identified a 39-CAG repeat allele within the reduced-penetrance range. The marked intergenerational expansion from 39 to 62 repeats and absence of an apparent family history highlight genetic anticipation and clinically silent parental carriage. Although paternal transmission predominates in JHD, this case demonstrates that substantial maternal transmission can occur. It also highlights the diagnostic importance of recognizing academic and behavioural deterioration as early manifestations of JHD and the role of cascade testing and genetic counselling in apparently sporadic pediatric cases.
Shaun Nevil, Amay Wattamwar, Pratyusha Dutta, Shreya Gupta, Kanishka Verma, Vishvas Ramala GK. Juvenile-Onset Huntington's Disease in a 12-Year-Old Girl: A Rare Case Report. Ann Case Rep Clin Stud. 2026;5(6):1-4.