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Clinical features of Chinese patients with Huntington's disease carrying CAG repeats beyond 60 within HTT gene

Z-J Liu1, Y-M Sun, W Ni

  • 1Department of Neurology and Institute of Neurology, Huashan Hospital, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai, China ; Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China.

Clinical Genetics
|February 13, 2013
PubMed

Insights

This study details four Chinese patients with Huntington's disease (HD) who have over 60 CAG repeats. These patients presented with early-onset, atypical symptoms, challenging early diagnosis.

Area of Science:

  • Genetics
  • Neurology
  • Clinical Medicine

Background:

  • Huntington's disease (HD) is a neurodegenerative disorder.
  • Patients with over 60 CAG repeats are rare and their clinical features are underreported.
  • Understanding these rare cases is crucial for comprehensive HD knowledge.

Purpose of the Study:

  • To investigate the clinical characteristics of Chinese Huntington's disease patients with expanded CAG repeat lengths (>60).
  • To highlight atypical early-onset symptoms that may lead to misdiagnosis.
  • To aid clinicians in the early and accurate diagnosis of severe HD cases.

Main Methods:

  • Direct sequencing was used to identify CAG repeat lengths in 119 Chinese HD patients.
  • Four unrelated patients with CAG repeat lengths ranging from 74 to 104 were identified.
  • Clinical features and onset symptoms of these four patients were analyzed.

Main Results:

  • All four identified patients exhibited early-onset HD, with a mean symptom onset age of 9.8 years.
  • Paternal transmission was observed in three patients; one case was sporadic.
  • Atypical symptoms included epilepsy, intellectual decline, tics, and walking instability.

Conclusions:

  • Patients with Huntington's disease and over 60 CAG repeats often present with early-onset and atypical symptoms.
  • These atypical presentations can mimic other neurological conditions, complicating early diagnosis.
  • Identifying these features can improve diagnostic accuracy for severe forms of Huntington's disease.

Keywords:
CAG repeats beyond 60HTTHuntington's disease

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