Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA.
Postgrad Med. 2011 Sep;123(5):116-21. doi: 10.3810/pgm.2011.09.2466.
To explore the clinical phenotype in individuals with huntingtin gene CAG repeat lengths between 27 and 35, a range that is termed "intermediate" and below one traditionally considered diagnostic of Huntington disease (HD).
The Prospective Huntington Disease At-Risk Observational Study (PHAROS) found that patients with intermediate CAG lengths overlapped with those diagnosed as HD (≥ 37 CAG repeats) on the Unified Huntington's Disease Rating Scale (UHDRS) behavioral measures. Furthermore, several patients with intermediate CAG repeats demonstrating clinical (and pathological) evidence of HD have been reported.
We reviewed all cases with intermediate CAG repeats who have presented to our clinic, as well as those reported in the literature.
We describe 4 patients with intermediate repeats evaluated at our center whose clinical features were highly suggestive of HD. Investigations for HD phenocopies were negative. Anticipation was demonstrated in 1 case with supportive neuropathological evidence of HD. Additionally, we describe the clinical features of 5 other patients reported in the literature.
Individuals with huntingtin gene CAG repeats in the intermediate (27-35) range should be considered at risk for the development of HD, particularly if they have a family history of HD, whether they exhibit clinical features of the disease.
探索亨廷顿基因 CAG 重复长度在 27 到 35 之间的个体的临床表型，这一范围被称为“中间”，低于传统上被认为是亨廷顿病 (HD) 诊断标准的范围。
前瞻性亨廷顿病风险观察研究 (PHAROS) 发现，在统一亨廷顿病评定量表 (UHDRS) 行为测量中，具有中间 CAG 长度的患者与被诊断为 HD（≥ 37 CAG 重复）的患者重叠。此外，已经报道了一些具有中间 CAG 重复的患者表现出临床（和病理）证据的 HD。
我们回顾了在我们诊所就诊的所有具有中间 CAG 重复的病例，以及文献中报道的病例。
我们描述了在我们中心评估的 4 例具有中间重复的患者，其临床特征高度提示 HD。对 HD 表型的研究均为阴性。在 1 例具有支持 HD 的神经病理学证据的病例中观察到了预期。此外，我们还描述了文献中报道的另外 5 例患者的临床特征。
亨廷顿基因 CAG 重复在中间（27-35）范围内的个体应被视为发展为 HD 的风险，特别是如果他们有 HD 的家族史，无论他们是否表现出疾病的临床特征。
