| Knowledge-base field | Summary | Ontology/identifier suggestions | Evidence status | Key citations |
|---|---|---|---|---|
| Disease / identifiers | Hyperprolinemia type 1 (HPI) is a rare inborn error of proline degradation caused by deficiency of proline dehydrogenase (PRODH, also called proline oxidase). It should be distinguished from hyperprolinemia type 2, which is due to ALDH4A1/P5CDH deficiency. Information here is disease-level, aggregated from literature and curated resources, not EHR-derived. | MONDO:0009400; MeSH/ICD/OMIM/Orphanet: verify in source database before KB ingestion | Established for disease concept and distinction from HPII | (pqac-00000000, pqac-00000001, pqac-00000003) |
| Causal gene / inheritance | Primary causal gene: PRODH (proline dehydrogenase 1). Inheritance is autosomal recessive. Open Targets links HPI most strongly to PRODH; other associations are much weaker and not sufficient to assign causality. | Gene: PRODH; HGNC/Ensembl can be added from gene database; MONDO:0009400 | Established for PRODH and AR inheritance; uncertain for other candidate associations | (pqac-00000000, pqac-00000001) |
| Biochemical defect | Loss or reduction of mitochondrial PRODH activity impairs oxidation of L-proline to P5C, disrupting the proline→P5C→glutamate pathway. Reported hallmark is elevated proline in plasma, CSF, and urine; urine may also contain glycine and hydroxyproline. Human reviews describe proline elevations up to ~10-fold above normal in PRODH defects. | GO suggestions: proline catabolic process; mitochondrial inner membrane; CHEBI: L-proline, glutamate | Established for elevated proline and pathway position; downstream neurotoxicity mechanisms remain partly inferred | (pqac-00000001, pqac-00000002, pqac-00000004, pqac-00000007, pqac-00000008) |
| Core phenotypes | Phenotype spectrum is highly variable: some individuals are asymptomatic, while reported manifestations include developmental delay/intellectual disability, behavioral problems, autism spectrum disorder, seizures/epilepsy, schizophrenia or schizoaffective phenotypes, nephropathy, and rare movement-disorder presentations. Nervous system involvement predominates in the literature. | HPO suggestions: Hyperprolinemia; Seizure; Developmental delay; Intellectual disability; Behavioral abnormality; Autism; Schizophrenia; Nephropathy | Mixed: hyperprolinemia is established; neuropsychiatric associations are reported but incompletely penetrant and sometimes confounded | (pqac-00000001, pqac-00000002, pqac-00000003) |
| Diagnosis | Diagnostic approach centers on elevated proline in plasma/CSF/urine plus molecular confirmation of PRODH variants. P5C measurement helps distinguish HPI from HPII. Differential diagnosis includes ALDH4A1-related HPII and secondary hyperprolinemia in syndromic contexts such as 22q11.2 deletion. | HPO: Hyperprolinemia; Gene testing: PRODH; Differential: ALDH4A1-related hyperprolinemia type 2 | Established for biochemical testing strategy; no universally standardized diagnostic criteria retrieved | (pqac-00000001, pqac-00000003) |
| Treatment | No proven disease-modifying therapy was identified. Review evidence states dietary proline restriction does not improve clinical manifestations. Current care is supportive and phenotype-directed (e.g., seizure, developmental, psychiatric management). A vitamin D trial targeting schizophrenia-associated hyperprolinemia was withdrawn before enrollment, so no efficacy data exist. | NCIT suggestions: Supportive care; Dietary management; Anticonvulsant therapy; Psychiatric management | Established absence of proven therapy in retrieved evidence; experimental vitamin D concept remains untested | (pqac-00000001, pqac-00000020, pqac-00000021) |
| Prognosis / course | Prognosis appears variable and often compatible with long survival, especially in mild or asymptomatic cases, but robust survival statistics were not retrieved. The course is usually chronic biochemical hyperprolinemia with heterogeneous neurologic/psychiatric expression rather than a clearly staged progressive disorder. | HPO suggestions depend on phenotype burden; no specific prognosis ontology added | Uncertain due to sparse natural-history data and small cohorts | (pqac-00000001, pqac-00000003) |
| Epidemiology / population | HPI is rare. Reliable prevalence, incidence, carrier frequency, sex ratio, and founder-mutation data were not retrieved in the available evidence set. In a 22q11.2 deletion cohort, 35% had hyperprolinemia, but that figure should not be used as HPI prevalence. | MONDO:0009400 | Rarity established; population statistics largely unavailable here | (pqac-00000012, pqac-00000016, pqac-00000017) |
| Model systems | Experimental evidence includes PRODH expression studies in U87 glioblastoma cells and Prodh-deficient mouse work discussed in reviews. Cell models show mitochondrial localization and effects on intracellular proline, glutamate, and glutamine; mouse literature supports relevance to sensorimotor-gating and neurobehavioral phenotypes, but not full recapitulation of human HPI heterogeneity. | CL suggestion: glial cell / astrocyte-like cell line context for U87; GO: mitochondrial inner membrane | Useful mechanistic support; translational limits should be noted | (pqac-00000004, pqac-00000005, pqac-00000009, pqac-00000010, pqac-00000011) |
| Key evidence caveats | Much of the neuropsychiatric literature is confounded by 22q11.2 deletion syndrome, where PRODH hemizygosity co-occurs with many other deleted genes and modifiers such as COMT. Reported associations with IQ, startle, schizophrenia, or ASD are inconsistent, often based on small samples, and should not be overinterpreted as universal features of isolated HPI. | Annotation note: tag psychiatric findings as variable/uncertain association | Important caution for KB curation | (pqac-00000012, pqac-00000013, pqac-00000014, pqac-00000015, pqac-00000016, pqac-00000017, pqac-00000018, pqac-00000019) |


*Table: This table provides a compact, evidence-weighted summary of Hyperprolinemia Type 1 for knowledge-base curation. It separates well-established disease facts from more uncertain neuropsychiatric associations and highlights where identifiers or epidemiologic values should be verified externally before ingestion.*