Inborn errors of cytoplasmic triglyceride metabolism

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• Cytoplasmic triglyceride metabolism (CTGM) encompasses synthesis, storage, and degradation of triglycerides (TGs).
• CTGM is primarily studied in adipocytes but is crucial in non-adipose tissues like muscle, liver, and myocardium.
• Dysregulation of CTGM can lead to steatosis and organ dysfunction.

Purpose of the Study:

• To review known inborn errors of CTGM and their associated phenotypes.
• To highlight the tissue-specific roles and complexities of CTGM.
• To emphasize the potential for identifying new CTGM-related disorders.

Main Methods:

• Literature review of known inborn errors of CTGM enzymes.
• Discussion of phenotypes associated with enzyme deficiencies.
• Comparison of human phenotypes with available mouse models.

Main Results:

• Deficiencies in enzymes like AGPAT2, LPIN1, DGAT1, ATGL, and HSL cause diverse conditions including lipodystrophy, rhabdomyolysis, and metabolic disorders.
• Inborn errors of glycerol metabolism (GK, GPD1) lead to pseudohypertriglyceridemia and hepatic steatosis.
• Less than one-third of CTGM enzymes have known associated inborn errors, suggesting further discoveries are possible.

Conclusions:

• Inborn errors of CTGM reveal its critical roles in various tissues beyond adipose cells.
• Understanding CTGM is essential for diagnosing and potentially treating a range of metabolic and genetic disorders.
• Further research into CTGM enzymes may uncover novel disease phenotypes.