Huntington Disease: Diagnosis and Diagnostic Testing, a Prospective Study
Objective:
Concerns have been raised about patient distress with diagnostic genetic testing. A one year prospective study of referral sources, illness stage, functional impairment, reaction to diagnosis and diagnostic testing was undertaken in new patients of the Huntington Disease (HD) Clinic.
Methods:
New presentations between Jan 06- 07 were assessed including UHDRS motor, functional and cognitive scores, distress and benefits of the diagnostic process and results of genetic testing.
Results:
Of 19 patients with possible HD, 16 were diagnosed. Most had impaired insight, function and cognition (mean UHDRS independence score 075, mean SDMT score –2.6). Diagnostic genetic testing was initiated in 9, with surrogate consent obtained in 3. Two with poor insight refused. Clarification of diagnosis with testing benefited all including two with negative tests. Distress mostly related to waiting for extra counseling and results. Benefits of clinical assessment (versus genetic test itself) included identification of problems requiring urgent management.
Conclusion:
It is not possible to avoid some distress to patient and family when considering or diagnosing HD. As manifestations can be helped, a duty of care exists to establish a clear diagnosis quickly, particularly when cognitive change impacts on function.
We conclude that the HD diagnostic test complements clinical assessment and is unlikely to cause extra distress beyond assessment and diagnosis overall. While consent from the patient, or a surrogate in the case of cognitive change, is required for diagnostic genetic testing, this should not be considered the same situation as predictive genetic testing.