HYPOCHOL : A Genetically-based Strategy to Identify New Targets in Cholesterol Metabolism

Hypobetalipoproteinemia Clinical Trial

— HYPOCHOL  

Official title:

HYPOCHOL : A Genetically-based Strategy to Identify New Targets in Cholesterol Metabolism

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT02354079
• Other study ID #: RC14_0400
• Status: Active, not recruiting
• Phase: N/A
• Start date: January 7, 2016
• Est. completion date: January 7, 2032

Study information

• Verified date: August 2023
• Source: Nantes University Hospital
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The aim of this study is to identify new targets in cholesterol metabolism thanks to a genetically-based strategy.

Description:

The goal is to recruit 400 subjects: 200 adult subjects with familial hypobetalipoproteinemia (FHBL) (index cases) plus 200 additional related subjects in at least 10 large informative FHBL families, in which there is no known mutation in FHBL genes.

The patient care is modified: patient will have an Hospital Anxiety and Depression (HAD) questionnaire (focus on depressive syndrome), a food diary, and some additional blood analysis (including genetic analysis).

One of the main issue to recruit FHBL patients is the fact that they are asymptomatic and that FHBL is not identified as a serious illness by their general physicians.

Step-1. Excluding mutations in selected candidate genes As a first approach to screen candidate genes and exclude patients with known mutations, the investigators developed a custom design based on the Haloplex™ technology (Agilent® Technologies) to perform high-throughput sequencing of the coding regions of 10 genes, including those previously described in FHBL (apolipoprotein B (APOB), Proprotein convertase subtilisin/kexin type 9 (PCSK9)), Microsomal triglyceride transfer protein (MTP or ABL), chylomicron retention disease (CMRD), Secretion associated, Ras related GTPase (SARA2 gene), as well as 6 additional candidate genes in cholesterol metabolism (low density lipoprotein receptor (LDLR), Sortilin (SORT1), Inducible Degrader of the LDL receptor (IDOL), Cholesteryl ester transfer protein (CETP), Apolipoprotein E (ApoE) and Angiopoietin-like Protein 3 (ANGTPL3)). All the recruited index cases (n=200) will be genotyped to select only those without mutations in previously described genes, being approximately 50% of our index case cohort.

Step-2. Identification of informative families and exome sequencing In patients without identified mutations, the investigators will conduct a familial screening in order to identify other cases of FHBL among proband relatives. An analysis of fasting plasma lipid parameters (total cholesterol (TC), High density lipoprotein cholesterol (HDL-C), Low-Density Lipoproteins (LDL-C) and triglycerides (TG)) will be performed for each related. Affected subjects will be determined by a spontaneous LDL-C < 80 mg/dl and/or apoB < 50 mg/dl. In contrast, non-affected subjects will display LDL-C > 80 mg/dl and/or apoB > 50 mg/dl.

For large families, the investigators will then combine whole-exome sequencing and linkage analysis to identify any novel genetic variant likely explaining FHBL. Depending on family pedigree, whole-exome sequencing (WES) will be performed on 2 to 5 patients per family. All relatives will be genotyped for linkage analysis.

In parallel to this genetic approach, a regional epidemiological analysis will be performed to identify some geographical clusters with a high prevalence of the disease, as developed in the project named VaCaRMe (for Vascular and Cardiac, Respiratory and Metabolic overcome diseases)

An additional aim, based on an exhaustive phenotyping of FHBL patients, is to investigate the safety of very low LDL-C and to perform some genotype-phenotype correlations in patients with FHBL population."

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 435
• Est. completion date: January 7, 2032
• Est. primary completion date: January 7, 2022
• Accepts healthy volunteers: No
• Gender: All
• Age group: N/A and older

Eligibility

Inclusion Criteria:

• For index cases without family screening:

o Patient with HBL: fasting LDL-C = 50 mg/dl.

• For familial affected cases:

• Relative with HBL: fasting LDL-C = 80 mg/dl and/or Apo B = 50 mg/dl and at least one related family case suffering from HBL.

All subjects, including familial non-affected cases, must give written consent (dated and signed) to participate at the constitution of biobank (including DNA samples and urine samples).

Exclusion Criteria:

• Use of lipid-lowering drugs (statins, fibrates, ezetimibe, bile-acid sequestering resin) or nutraceuticals known to affect lipids (red yeast rice, margarine and dairy with plant sterol)

• Patient screened within an extreme metabolic disturbance (emergency situations, sepsis, hospitalization in intensive care unit)

• Patients with hyperthyroidism, severe liver failure, end stage chronic kidney disease, serious pancreatic failure, anemia related to thalassemia or sickle cell disease, strict vegan diet or malnutrition

• Refusal of the patient or his legal representative to participate in the study"

Related Conditions & MeSH terms

• Hypobetalipoproteinemia
• Hypobetalipoproteinemias

Intervention

Genetic:
• hypobetalipoproteinemia genetic and genotypic screening

Locations

Country	Name	City	State
France	CHU de Nantes	Nantes

Sponsors (1)

Lead Sponsor	Collaborator
Nantes University Hospital

Country where clinical trial is conducted

France, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	number of phenotypes associated to genotype of FHBL and very low LDL-C	To determine number of phenotypes associated to genotype of FHBL and very low LDL-C. (Liver steatosis, Glucose homeostasis, Cancer, Depression scores, Cardiovascular diseases).	ten years
Primary	type and number of genetic abnormalities leading to FHBL	To identify new gene involved in FHBL and determine genetic cause of FHBL (Patients with FHBL and their relatives will be recruited to establish familial forms of FHBL in large informative families with no mutations in known classical FHBL genes. This will allow perform genetic analysis using new approaches to genetic broadband (exome sequencing analysis + linkage analysis). This approach will allow specify which chromosomal regions are shared only by affected individuals, and identify new candidate genes).	ten years