Home > Gene Browser > APOB

APOB

Synonyms
FCHL2, FLDB, LDLCQ4, apoB-100, apoB-48
External resources
Summary
This gene product is the main apolipoprotein of chylomicrons and low density lipoproteins (LDL), and is the ligand for the LDL receptor. It occurs in plasma as two main isoforms, apoB-48 and apoB-100: the former is synthesized exclusively in the gut and the latter in the liver. The intestinal and the hepatic forms of apoB are encoded by a single gene from a single, very long mRNA. The two isoforms share a common N-terminal sequence. The shorter apoB-48 protein is produced after RNA editing of the apoB-100 transcript at residue 2180 (CAA->UAA), resulting in the creation of a stop codon, and early translation termination. Mutations in this gene or its regulatory region cause hypobetalipoproteinemia, normotriglyceridemic hypobetalipoproteinemia, and hypercholesterolemia due to ligand-defective apoB, diseases affecting plasma cholesterol and apoB levels.

Variant counts

The variants found in rare patients tested by 3billion are classified and counted according to ACMG guidelines. The variants with over 5% variant frequency in population genome databases ( gnomAD, dbSNP, etc) are excluded.

Pathogenic
48
Likely pathogenic
18
VUS
6,805
Likely benign
8,538
Benign
5,286

Patient phenotypes

Proportions of phenotypes among 50 patients carrying pathogenic or likely pathogenic variants on APOB gene are displayed below.

Phenotype class
Patients in 3billion (%)
Abnormality of the nervous system
42%
Abnormality of the cardiovascular system
34%
Abnormality of head or neck
32%
Abnormality of the musculoskeletal system
28%
Abnormality of the eye
24%
Abnormality of the integument
24%
Growth abnormality
18%
Abnormality of the ear
16%
Abnormality of limbs
12%
Abnormality of the genitourinary system
8%
Abnormality of blood and blood-forming tissues
4%
Abnormality of the digestive system
4%
Neoplasm
4%
Abnormality of prenatal development or birth
2%
Abnormality of the endocrine system
2%
Abnormality of the immune system
2%
Abnormality of the respiratory system
2%
Abnormal cellular phenotype
0%
Abnormality of metabolism homeostasis
0%
Abnormality of the breast
0%
Abnormality of the thoracic cavity
0%
Abnormality of the voice
0%
Constitutional symptom
0%

Have a question or need assistance? Ask here.

Send us your questions or comments related to the variant counts and/or patient phenotypes