| Domain | Key facts | Evidence |
|---|---|---|
| Disease identifiers & synonyms | **Disease:** Autosomal recessive primary microcephaly; **MONDO:** `MONDO_0016660`; related locus-specific MONDO terms include **microcephaly 1, primary, autosomal recessive** (`MONDO_0009617`) and subtype entries for specific MCPH loci. Common synonyms: **MCPH**, **primary hereditary microcephaly**, **microcephaly primary hereditary**, **congenital primary microcephaly**, **microcephaly vera**. Disease-level information is derived from aggregated disease resources plus case-series/case-report literature rather than EHR-only data. (pqac-00000000, pqac-00000003) | OpenTargets disease-target association for `MONDO_0016660`; Farcy et al. 2023, *Cells* 12:1807, DOI: https://doi.org/10.3390/cells12131807 (pqac-00000000, pqac-00000003) |
| Clinical definition & onset | MCPH is a **congenital/prenatal-onset** brain growth disorder with reduced OFC detectable **at or before birth**. Common cutoffs: **OFC < -2 SD** defines microcephaly; **severe** often **< -3 SD**. Some reviews emphasize MCPH as head circumference **>3 SD below mean** for age/sex. Brain growth slowdown may begin early in gestation, with prenatal detection often possible by **second-trimester ultrasound**; fetal MRI is often used later for characterization. (pqac-00000003, pqac-00000007, pqac-00000004, pqac-00000013) | Farcy et al. 2023, *Cells*, DOI above; Wu et al. 2023, *Front Neurosci* 17, DOI: https://doi.org/10.3389/fnins.2023.1242448; mechanistic review/prenatal summary from Ivanova excerpt. (pqac-00000003, pqac-00000007, pqac-00000004, pqac-00000013) |
| Epidemiology | Reported prevalence/incidence varies widely by ascertainment and consanguinity context: **~1/30,000 to 1/250,000 live births** is a recurrent MCPH range; broader fetal/congenital microcephaly incidence estimates include **1.3-150 per 10,000 live births**. Severe PM prevalence was reported as **~0.5-1 per 1,000 live births** in one review context, though that broader figure is not specific to AR-MCPH subtypes. Higher prevalence is repeatedly linked to populations with **high consanguinity**. (pqac-00000005, pqac-00000013, pqac-00000007, pqac-00000009) | Chen et al. 2024, *Front Neurol* 15, DOI: https://doi.org/10.3389/fneur.2024.1341864; Wu et al. 2023, *Front Neurosci*; Farcy et al. 2023, *Cells*; Wang et al. 2023, *Front Genet* 14, DOI: https://doi.org/10.3389/fgene.2023.1112153. (pqac-00000005, pqac-00000013, pqac-00000007, pqac-00000009) |
| Top causal genes & estimated contribution | **ASPM** is the most frequent MCPH gene: estimated **~40%** of patients in a 2023 ASPM review; **~50%** of cases in a 2024 WDR62 case report/review; a 2026 Pakistani series reported **68%**. **WDR62** is typically second most common: **~10%** of cases in Chen et al. 2024; **~14%** in the Pakistani 2026 series. OpenTargets also ranks **WDR62, ASPM, CDK5RAP2, CEP152, MCPH1, KIF14, ANKLE2, ZNF335, CIT, STIL, CEP135, KNL1** among top disease-associated targets for `MONDO_0016660`. (pqac-00000005, pqac-00000013, pqac-00000000, pqac-00000006) | Wu et al. 2023, *Front Neurosci*; Chen et al. 2024, *Front Neurol*; OpenTargets `MONDO_0016660`; Farooq et al. 2026, *Front Genet* 16, DOI: https://doi.org/10.3389/fgene.2025.1709083. (pqac-00000005, pqac-00000013, pqac-00000000, pqac-00000006) |
| Common neuroimaging findings | Frequent MRI features include **reduced brain volume**, **simplified gyral pattern/gyral simplification**, and variable **malformations of cortical development**. Reported abnormalities include **polymicrogyria**, **pachygyria**, **schizencephaly**, **heterotopia**, **lissencephaly/microlissencephaly**, **corpus callosum abnormalities**, and **mild cerebellar/pontine hypoplasia**. For **WDR62**, cortical malformations are particularly emphasized, including **neuronal heterotopia, pachygyria, schizencephaly, microlissencephaly**. (pqac-00000005, pqac-00000007, pqac-00000011) | Chen et al. 2024, *Front Neurol*; Farcy et al. 2023, *Cells*; Létard et al. 2018, *Hum Mutat* 39:319-332, DOI: https://doi.org/10.1002/humu.23381. (pqac-00000005, pqac-00000007, pqac-00000011) |
| Diagnostic testing & yields | **Recommended testing workflow:** prenatal/postnatal phenotyping + **CMA** for copy-number changes + **exome sequencing** (preferably trio) when CMA is non-diagnostic; confirmatory segregation/functional assays may include **Sanger**, **RT-PCR**, **Western blot** for splice/protein effects. In a fetal microcephaly cohort (**224 fetuses**), **CMA yield = 3.74% (7/187)** and **trio-ES yield = 19.14% (31/162)**; **VUS = 20.3% (33/162)**. ES identified **31 P/LP SNVs in 25 genes**, with **19/31 (61.29%) de novo** in that prenatal cohort. WES is highlighted as especially useful because routine prenatal screening misses many pathogenic single-gene causes. (pqac-00000009, pqac-00000005, pqac-00000010) | Wang et al. 2023, *Front Genet*, DOI above; Chen et al. 2024, *Front Neurol* (WES + Sanger/RT-PCR/Western blot example); prenatal MCD review stressing combined CMA+WES. (pqac-00000009, pqac-00000005, pqac-00000010) |
| Counseling & real-world implementation | Real-world implementation focuses on **molecular diagnosis for recurrence-risk counseling**, **prenatal testing**, and **family planning**, especially in consanguineous families. Literature explicitly notes that genetic diagnosis should be pursued even when environmental causes are suspected, because a confirmed diagnosis enables **precise counseling** and guides future pregnancies. Prenatal counseling reviews emphasize that early cause identification is essential because fetal microcephaly is often **lifelong and incurable**. (pqac-00000005, pqac-00000009, pqac-00000004) | Chen et al. 2024, *Front Neurol*; Wang et al. 2023, *Front Genet*; Chien & Chen 2024, *J Med Ultrasound* 32, DOI: https://doi.org/10.4103/jmu.jmu_18_23 (captured in search results); Ivanova excerpt on current untreatability and supportive care. (pqac-00000005, pqac-00000009, pqac-00000004) |
| 2023-2024 mechanistic/model advance: WDR62 human iPSC/organoids | **Dell'Amico et al. 2023, eLife** used patient-derived and isogenic-corrected **iPSCs**, generating **2D/3D human neurodevelopmental models** including neuroepithelial stem cells, cortical progenitors, neurons, and **cerebral organoids**. They showed **WDR62 localizes to the Golgi apparatus during interphase** and **translocates to spindle poles in a microtubule-dependent manner**; WDR62 dysfunction **impairs mitotic progression** and alters **neurogenic trajectories**, supporting a spindle/Golgi trafficking mechanism in human corticogenesis. DOI/URL: https://doi.org/10.7554/eLife.81716 (pqac-00000005) | Dell'Amico et al. 2023, *eLife* 12:e81716, DOI above. (pqac-00000005) |
| 2024 mechanistic/model advance: CIT forebrain organoids | **Pallavicini et al. 2024, JCI** created **CIT kinase-dead (CITKI/KI)** and **frameshift LOF (CITFS/FS)** mouse and **human forebrain organoid** models for MCPH17. Human organoids showed **loss of cytoarchitectural complexity**, transition from **pseudostratified to simple neuroepithelium**, **NPC cytokinesis polarity defects**, increased **DNA damage** and **apoptosis**. Importantly, the kinase-dead mouse did **not** phenocopy human microcephaly, highlighting species-specific vulnerability and the value of human organoids. DOI/URL: https://doi.org/10.1172/JCI175435 (pqac-00000005) | Pallavicini et al. 2024, *J Clin Invest* 134(21), DOI above. (pqac-00000005) |
| 2024 translational/modeling advance: reproducible CDK5RAP2 organoids | **Ramani et al. 2024, Nat Commun** developed scalable **Hi-Q brain organoids** with improved reproducibility and lower stress artifacts, then used **patient-derived organoids** to recapitulate **primary microcephaly due to centrosomal CDK5RAP2 mutation**. The platform was proposed as useful for **personalized disease modeling** and **drug screening**, addressing a major reproducibility barrier in organoid-based MCPH studies. DOI/URL: https://doi.org/10.1038/s41467-024-55226-6 (pqac-00000005) | Ramani et al. 2024, *Nature Communications* 15, DOI above. (pqac-00000005) |
| 2024 mechanistic advance: spindle flux/lagging chromosome hypothesis | A 2024 preprint by **Doria et al.** proposed that loss of **ASPM/WDR62** slows **poleward microtubule flux**, causing **transient lagging chromosomes**, **Aurora-B-dependent 53BP1 activation**, **p21 induction**, and reduced cell proliferation; CAMSAP1/Patronin suppression rescued phenotypes in cell and Drosophila models. This is a notable emerging hypothesis but remains **preprint/non-peer-reviewed** in the retrieved evidence. DOI/URL: https://doi.org/10.1101/2024.05.02.592199 (pqac-00000005) | Doria et al. 2024, *bioRxiv*, DOI above. (pqac-00000005) |


*Table: This table condenses identifiers, epidemiology, major genes, imaging findings, diagnostic yields, and key 2023-2024 mechanistic/modeling advances for autosomal recessive primary microcephaly. It is designed as a high-density reference for knowledge-base entry drafting and citation mapping.*