Gene therapy for treating a rare cholesterol disorder

Inclusion Criteria:

* Voluntarily sign informed consent form;
* Male or female, 12 ≤ age ≤ 55 years (first patient≥ 18 years), diagnosed as homozygous familial hypercholesterolemia with genetic confirmation of two mutant alleles of the LDL receptor (LDLR) gene;
* AAV8 neutralizing antibodies can be negative or reduced to negative levels through methods such as plasma exchange or IgG-degrading enzymes.
* Untreated LDL-C ≥10 mmol/L (386mg/ dL) or treated LDL-C ≥7 mmol/L (270mg/ dL) together with cutaneous or tendon xanthoma before age 18 years;
* Had been on stable medication for ≥30 days if receiving lipid-lowering therapy (or ≥60 days if receiving alirocumab or evolocumab) prior to screening and not scheduled for addition of new drugs or dose adjustments during the study;
* Agreed to follow a low-fat diet and comply with all study procedures, including dietary requirements, study visits, fasting blood draws, and the study treatment regimen.;
* Agreed to maintain a similar exercise volume and intensity to baseline during the study period;
* Agreed to maintain good lifestyle habits;
* No history of alcohol abuse or alcohol dependence (diagnosed as F10 in ICD-10 code);
* No sexual activity for 14 days prior to administration and negative serum pregnancy test in female participants;
* Participants of childbearing potential agreed to use highly effective contraception for at least 365 days from administration of NGGT006;
* No plan of stent implantation within 3 months.

Exclusion Criteria:

* Positive for hepatitis B surface antigen, hepatitis C, human immunodeficiency virus (HIV) or syphilis test;
* Clinically significant abnormalities in liver function test: alanine aminotransferase (ALT) \>3 × upper limit of normal (ULN) and/or aspartate aminotransferase (AST) \>3 × ULN;
* Baseline blood pressure \>160/100 mmHg (1 repeat measurement is allowed);
* Uncontrolled myocardial infarction or heart failure, or had surgery plan within 1 year;
* Diabetes diagnosed within 3 months or with poor control (HbA1c \>9%);
* Acute or chronic kidney failure;
* Hemoglobin (Hb) \<120g/L (male), Hb \<110 (female);
* Platelet test results deemed clinically significantly abnormal by the investigator;
* History or laboratory tests suggestive of thrombosis;
* Had contraindications to glucocorticoid (e.g., epilepsy, severe schizophrenia, active peptic ulcer);
* Life expectancy less than 1 year;
* With malignant tumors;
* Liver fibrosis or liver cancer;
* Previous gene therapy treatment;
* Hypersensitivity to any excipient of the AAV product (including trehalose) or cortisone or immunosuppressants (sirolimus, rituximab, tacrolimus);
* Participation in any other clinical trial within 3 months;
* History of stent implantation within 1 month or myocardial infarction within 3 months;
* Breastfeeding females;
* Any other condition that may not be appropriate for the study in the opinion of the Investigator.