Inclusion Criteria:

1. Non-obese** patients with elevated low-density lipoprotein (LDL)
2. Non-obese** patients with low high-density lipoprotein (HDL)
3. Non-obese** patients with unexplained and persistently elevated liver transaminases,
4. Non-obese** patients with hepatomegaly
5. Patients with cryptogenic cirrhosis
6. Patients with biopsy-proven microvesicular or mixed micro/macrovesicular steatosis without a known etiology
7. Patients with presumed Familial Hypercholesterolemia (FH) in which genetic analysis was performed for the genes encoding the low-density lipoprotein receptor (LDLR), Apo-B and PCSK9 genes and no disease-causing mutations were identified
8. Patients with presumed FH with unclear family history
9. Patients with autosomal recessive hypercholesterolemia (other than homozygous FH)
10. Patients with autosomal recessive low HDL of unknown etiology

Also, patient must meet the following:

• Patient or patient's parent or legal guardian (if applicable) consents to participate in the study and provides informed consent prior to any study procedures being performed. If the patient is of minor age; he/she is willing to provide assent where required per local regulations, and if deemed able to do so.
• Patient is willing and able to comply with protocol requirements.
• Patients who do not fall into one of the aforementioned categories (cohorts) but are considered highly suspicious for LAL D should be tested to rule out the disorder outside of the study at the discretion of the Investigator.

Exclusion Criteria:

• Active viral hepatitis;
• Other confirmed genetic liver diseases (e.g., Wilson's disease, hemochromatosis, alpha 1-antitrypsin).