Gut Microbiomes in HD

* Inclusion Criteria: * 18 years or older * Provide informed consent * Able to read and speak English * Agree to comply with study procedures * Inclusion criteria for the control group include: * CAG repeat length ≤ 26. * BMI 18.5-24.9 * Inclusion criteria for experimental group 1 include: * BMI \< 18.5 (underweight) or significant, involuntary weight loss within the past 12 months. * CAG repeat length 40 - 59. * Documentation of the Clinical Diagnosis of HD with a high level of certainty (\>99% confidence) using the validated Unified Huntington's Disease Rating Scale (UHDRS). * Stage I-III on the Functional Assessment component of the UHDRS * Inclusion criteria for experimental group 2 include: * BMI \> 25.0 (overweight - obesity) or BMI ≤ 25.0 with significant, unexplained weight gain within the past 12 months * CAG repeat length 40 - 59. * Documentation of the Clinical Diagnosis of HD with a high level of certainty (\>99% confidence) using the validated UHDRS. * Stage I-III on the Functional Assessment component of the UHDRS * Exclusion Criteria: * CAG repeat length ≥ 60 to exclude participants with juvenile onset HD. * CAG repeat length 36 - 39 to exclude participants with reduced penetrance. As this is a pilot study, we are primarily interested in participants with typical HD characteristics. * UHDRS Functional Capacity stage ≥ 4 to exclude late-stage HD patients who may be institutionalized and receive nutrition through a feeding tube. * Use of any of the following drugs within the last 6 months: * System antibiotics, antifungals, antivirals, or anti-parasitics (intravenous, intramuscular, or oral) * Corticosteroids (intravenous, intramuscular, oral, nasal, or inhaled) * Cytokines * Methotrexate, immunosuppressive cytotoxic agents, or chemotherapy * Commercial probiotics ≥ 100 million CFU (fermented foods, yogurts, and other homeopathic probiotics and prebiotics do not apply) * Use of topical antibiotics or topical steroids within the last 7 days * History of active, uncontrolled gastrointestinal disorders or diseases, including: * Inflammatory bowel disease * Ulcerative colitis * Crohn's disease * Irritable bowel syndrome * Infectious gastroenteritis, colitis, or gastritis * Clostridium difficile or Helicobacter pylori infection * Persistent or chronic constipation or diarrhea * Acute illness with or without fever at time of sample collection * Positive for HIV, hepatitis B, or hepatitis C * Confirmed or suspected immunodeficient condition/state * Major surgery of the GI tract, excluding cholecystectomy and appendectomy * Unstable dietary history within the past month, such as elimination or significant increase of a major food group in the diet * Recent history of chronic, excessive alcohol consumption * Travel outside of the United States within the last 3 months