Mitochondrial Lipoylation Disorders

Overview

This project curates the three known disorders of the mitochondrial protein lipoylation pathway. Lipoylation is a post-translational modification essential for the function of four mitochondrial enzyme complexes: pyruvate dehydrogenase (PDH), alpha-ketoglutarate dehydrogenase (OGDH), branched-chain alpha-ketoacid dehydrogenase (BCKDH), and the glycine cleavage system (GCS). The three enzymes of the lipoylation pathway form a linear biosynthetic chain:

Octanoyl-ACP → [LIPT2] → Octanoyl-GCSH → [LIAS] → Lipoyl-GCSH → [LIPT1] → Lipoylated E2 subunits (PDH/OGDH/BCKDH)

Deficiency of any enzyme in this pathway causes severe neonatal/infantile mitochondrial disease with lactic acidosis and neurological involvement. All three are ultra-rare (<20 patients reported worldwide).

Goals

• Curate all three lipoylation pathway disorders with evidence-backed pathophysiology
• Map phenotypes to HPO terms with frequency data where available
• Annotate treatments with NCIT terms
• Capture genotype-phenotype distinctions (e.g., LIPT1 spares glycine cleavage)
• Provide PMID-supported evidence for all mechanistic and clinical claims

Key Biochemical Distinctions

Target Conditions

• [x] NELABA (LIPT2 deficiency) - NELABA.yaml - Created 2026-02-10, 89.4% compliance
• [x] Lipoic Acid Synthetase Deficiency (LIAS) - Lipoic_Acid_Synthetase_Deficiency.yaml - Created 2026-02-10, 91.7% compliance
• [x] Lipoyl Transferase 1 Deficiency (LIPT1) - Lipoyl_Transferase_1_Deficiency.yaml - Created 2026-02-10, 90.9% compliance

Key References

Deep Research Summary

Deep research was conducted using falcon and cyberian providers.

Falcon

• NELABA: Returned wrong disease (NAXD/NAXE instead of LIPT2). Unreliable for this ultra-rare disorder.
• LIAS: Completed. Found pathway-level papers (Fe-S clusters, ferredoxins) but missed key clinical papers (Baker 2014). Useful for discovering Bick 2024.
• LIPT1: Best results. Discovered Bick 2024 (lplA therapy + new patient with sideroblastic anemia) and Gómez-Fernández 2024 (pharmacological cocktail rescue).

Cyberian

• All 3 jobs failed with server errors (500 / connection refused). No results.

Assessment

For ultra-rare Mendelian disorders, direct PubMed/OMIM-guided curation was the primary driver of quality. Deep research served as a supplementary discovery tool for newer publications but missed foundational clinical case reports and had disease confusion issues.

Future Work

• [ ] Add phenotype context blocks with onset and frequency data as more cases are published
• [ ] Monitor for new LIPT2/LIAS/LIPT1 case reports to update patient counts
• [ ] Track progress of lplA gene therapy approach (Bick 2024) through preclinical studies
• [ ] Track Gómez-Fernández 2024 multi-target cocktail approach for LIPT1
• [ ] Consider adding related Fe-S cluster disorders (BOLA3, NFU1, ISCA2) that secondarily affect lipoylation
• [ ] Add cardiomyopathy phenotype to LIAS if verifiable reference found (mentioned in full text of Mayr 2011)

Curation Workflow

1. Create YAML file in kb/disorders/
2. Validate with just validate <file> and just validate-kb-references <file>
3. Validate terms with just validate-terms <file>
4. Run just qc before committing