Liver function may change how venglustat works in the body

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Participant must be 18 to 79 years of age inclusive, at the time of signing the informed consent. * Body weight between 50.0 and 115.0 kg, inclusive, if male; between 40.0 and 100 kg, inclusive, if female, and body mass index (BMI) within the range 18 to 40 kg/m2, inclusive, at screening. * Contraception (with double contraception methods) for male and female participants; not pregnant or breastfeeding for female participants; no sperm donation for male participants. * Female participants must refrain from donating ova/ovum. * Capable of giving signed informed consent. Participants with mild, moderate, and severe hepatic impairment * Stable chronic liver disease assessed by medical history, physical examination, and laboratory values. Hepatic impairment will be assessed according to the Child-Pugh classification, using CPS (Mild hepatic impairment is defined as a total score ranging from 5 to 6, inclusive (CPS-A); Moderate hepatic impairment is defined as a total score ranging from 7 to 9, inclusive (CPS-B); and severe hepatic impairment is defined as a total score ranging from 10 to 15, inclusive (CPS-C). * Laboratory parameters within the acceptable range for participants with hepatic impairment; however, serum creatinine should be strictly at or below the upper laboratory norm and eGFR should be \>= 60 mL/min. Participants with normal hepatic function * Certified as healthy by a comprehensive clinical assessment (detailed medical history and complete physical examination). * Laboratory parameters within the reference range for healthy participants. Exclusion Criteria: * Participant who had severe course of COVID-19 (i.e., hospitalization, extracorporeal membrane oxygenation, mechanically ventilated) within the past 8 weeks. * History of current recreational drugs or alcohol abuse. * Smoking more than 15 cigarettes or equivalent per day. * Symptomatic postural hypotension, whatever the decrease in blood pressure, or asymptomatic postural hypotension defined as a decrease in SBP ≥30 mmHg within 3 minutes when changing from supine to standing position at screening and Day 1. * Blood donation within 2 months before inclusion. * Positive result on drug or alcohol screen. * Sensitivity to any of the study interventions, or components thereof, or drug or other allergy that, in the opinion of the Investigator, contraindicates participation in the study. * Any consumption of citrus fruits (grapefruit, orange, etc) or their juices within 5 days before inclusion). * Any participant who cannot comply with the following study restrictions: refraining from drinking alcohol, tea, coffee, chocolate, quinine, or caffeine-containing beverages from 1 day before institutionalization and throughout the study duration; following a stable lifestyle with no intensive physical activity from 1 day prior to institutionalization throughout the study duration until after collection of the final PK sample. * Positive result on anti-human immunodeficiency virus (HIV) or COVID-19 test. Participants with mild, moderate, and severe hepatic impairment * Hepatocellular carcinoma. * Acute hepatitis. * Uncontrolled or decompensated hepatic encephalopathy. Encephalopathy grade \> 2. * Any drug (within 14 days before inclusion or within 5 times the elimination half-life or pharmacodynamic half-life of the medication) which could impact by any mechanism of action, the pharmacokinetics of the investigational medicinal product, including moderate and strong CYP3A4 inhibitors or inducers. * Any participant enrolled in or having participated in this or any other clinical study involving an IMP or in any other type of medical research according to applicable regulations within the past 14 days or 5 half-lives before screening, whichever is longer, per local regulations. Participants with normal hepatic functions * Any history or presence of clinically relevant hepatic or renal disease. * Any medication (including St John's Wort) within 14 days before inclusion or within 5 times the elimination half-life or pharmacodynamic half-life of the medication, with the exception of hormonal contraception or menopausal hormone replacement therapy; any vaccination within the last 28 days and any biologics (antibody or its derivatives) given within 4 months before inclusion. * Current enrollment OR past participation in another investigational study in which an investigational intervention (eg, drug, vaccine, invasive device) was administered within the last 14 days or 5 half-lives days before screening, whichever is longer per local regulations. The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.