| Domain | Key finding | Quantitative detail | Evidence type/source |
|---|---|---:|---|
| Disease identifiers | NF1 microdeletion syndrome corresponds to chromosome 17q11.2 deletion syndrome, 1.4 Mb; Orphanet term is 17q11 microdeletion syndrome | MONDO:0013357; Orphanet:97685 | Aggregated disease resources plus literature linkage (pqac-00000000, pqac-00000001) |
| Definition | Constitutional heterozygous deletion of NF1 and flanking genes causes a generally more severe NF1 subtype | Large deletions account for ~5–11% of NF1 cases | Review/human cohort (pqac-00000002, pqac-00000004) |
| Deletion type 1 | Recurrent type-1 deletion mediated by low-copy repeats; classic severe form | ~1.4 Mb; ~70–80% of NF1 microdeletions | Human cohort/review (pqac-00000001, pqac-00000002, pqac-00000004) |
| Deletion type 2 | Recurrent type-2 deletion, often mosaic, mediated by SUZ12/SUZ12P1 recombination | ~1.2 Mb; ~10% of NF1 microdeletions | Human cohort/review (pqac-00000001, pqac-00000002, pqac-00000004) |
| Deletion type 3 | Rare recurrent type-3 deletion | ~1.0 Mb; ~1–4% of NF1 microdeletions | Human cohort/review (pqac-00000001, pqac-00000002, pqac-00000004) |
| Principal genes | Core deleted interval includes NF1 with clinically relevant co-deleted genes/modifiers | Key genes highlighted: NF1, SUZ12, RNF135, CRLF3, ADAP2 | Human cohort/review/organoid/OpenTargets (pqac-00000000, pqac-00000002, pqac-00000004, pqac-00000008) |
| Epidemiology | NF1 microdeletion syndrome is rare in the population but enriched within NF1 cohorts | Approx. 1 in 60,000 individuals; ~5% of NF1 in one estimate | Review (pqac-00000005) |
| Severe phenotype | Compared with intragenic NF1 variants, patients more often show dysmorphism, overgrowth, developmental and cognitive problems, and high tumor burden | Reported more often in type-1 than atypical deletions; age-dependent expression noted | Human cohort/review (pqac-00000003, pqac-00000004, pqac-00000006) |
| Malignancy risk | Increased malignant peripheral nerve sheath tumor risk, especially with SUZ12 co-deletion | Lifetime MPNST risk ~16–26% vs ~8–13% in general NF1 | Review/human cohort (pqac-00000001, pqac-00000004) |
| Diagnostics | Copy-number testing is central because sequencing alone can miss the syndrome | MLPA used for efficient detection/classification; chromosomal microarray/aCGH used for confirmation and breakpoint definition | Human cohort/review (pqac-00000003, pqac-00000007) |
| Core mechanism | NF1 haploinsufficiency reduces neurofibromin dosage, dysregulating RAS-MAPK signaling; co-deletion of SUZ12 implicates PRC2 biology in tumor risk | NF1 loss is the primary driver; SUZ12 loss linked to higher MPNST susceptibility | Review/human cohort (pqac-00000002, pqac-00000004) |
| Neurodevelopment mechanism | CRLF3 loss contributes to abnormal neurogenesis independent of NF1-driven NSC proliferation effects | Organoid study showed rescue of neuronal maturation defects with RhoA activation | Patient-derived iPSC cerebral organoid study (pqac-00000008, pqac-00000009) |
| 2024 mechanistic update | Beyond haploinsufficiency, a 2024 study showed chromatin reorganization and position effects on flanking genes | 4C-seq identified altered DNA-DNA interactions, including RHOT1 promoter interaction with SLC6A4 and increased SLC6A4 expression | Human molecular study, 2024 (pqac-00000002) |
| Surveillance | High-risk NF1 management principles apply; NF1 microdeletion involving SUZ12 is specifically recognized as higher risk | Baseline whole-body MRI recommended after puberty/late adolescence; closer follow-up for high internal tumor burden or DNL | 2024 surveillance guidance (pqac-00000012) |
| Treatment | No syndrome-specific curative therapy; care is standard NF1 complication-directed management with tumor surveillance and treatment as indicated | MEK inhibitors are used for NF1 complications such as symptomatic inoperable plexiform neurofibromas, not specifically for the microdeletion itself | Guideline/review/clinical-trial context (pqac-00000012, pqac-00000001) |


*Table: This table condenses the key knowledge-base facts for NF1 microdeletion syndrome, including identifiers, recurrent deletion classes, major co-deleted genes, core clinical risks, mechanisms, diagnostics, surveillance, and treatment framing. It is aligned to the gathered evidence and highlights where 2024 studies added mechanistic and surveillance updates.*