| Category | Item | Details/real-world implementation | Suggested ontology term (LOINC/MAXO where applicable) | Evidence/notes | Key sources (citation ids) |
|---|---|---|---|---|---|
| Diagnostics | Brain MRI | Core radiologic pattern in classic ADGRG1-related BFPP is symmetric bilateral frontoparietal polymicrogyria with a decreasing anterior-to-posterior gradient, patchy/random white-matter abnormalities, and cerebellar/brainstem hypoplasia; atypical cases may show diffuse polymicrogyria, hypomyelination, thin corpus callosum, ventriculomegaly, or pachygyria/lissencephaly-like changes. MRI is the frontline real-world diagnostic modality. | MAXO: brain MRI; LOINC-style concept: Magnetic resonance imaging of brain | Hallmark imaging clue; brainstem/cerebellar involvement helps distinguish ADGRG1-related disease from some broader PMG categories. Early MRI can occasionally be normal, so repeat imaging may be needed. | (pqac-00000001, pqac-00000009, pqac-00000034, pqac-00000043, pqac-00000045) |
| Diagnostics | EEG | EEG is used for seizure characterization and longitudinal management; reported findings include predominantly frontal spikes/spike-waves, multifocal spikes, generalized slow spike-and-wave complexes, and tonic seizures during sleep in severe epileptic encephalopathy/Lennox-Gastaut presentations. | LOINC-style concept: Electroencephalogram study; MAXO: electroencephalographic monitoring | Supports phenotyping of high-burden epilepsy; abnormalities are variable and reflect seizure syndrome rather than disease specificity. | (pqac-00000003, pqac-00000006, pqac-00000041) |
| Diagnostics | Whole-exome sequencing (WES) | Recommended high-yield molecular test in suspected ADGRG1-related BFPP, especially with PMG plus cerebellar/brainstem findings or consanguinity. In the 2024 family report, WES used Illumina NovaSeq paired-end sequencing, alignment with BWA-MEM2, SNV/indel calling with GATK, and annotation/classification with ACMG-based pipelines. | MAXO: exome sequencing | Useful early when neuroradiologic interpretation is uncertain or when imaging overlaps infection/cobblestone phenotypes. | (pqac-00000042, pqac-00000043, pqac-00000044) |
| Diagnostics | Targeted NGS panel | Real-world alternative/adjunct to WES: targeted next-generation sequencing panels for brain morphogenesis/malformations of cortical development can detect ADGRG1 variants, as shown in the 2021 case. | MAXO: targeted gene panel sequencing | Practical in clinical neurogenetics workflows where phenotype strongly suggests a malformation-of-cortical-development disorder. | (pqac-00000041, pqac-00000045) |
| Diagnostics | Sanger segregation testing | After candidate variant detection, familial segregation by Sanger sequencing is used to confirm biallelic inheritance and carrier status in parents/siblings. | MAXO: Sanger sequencing; MAXO: genetic testing of family members | Important for confirming autosomal recessive inheritance and informing recurrence risk/cascade testing. | (pqac-00000041, pqac-00000042, pqac-00000045) |
| Diagnostics | Variant interpretation | Variant interpretation should follow ACMG/AMP principles, incorporating rarity in population databases, predicted loss-of-function mechanism, in silico tools, and segregation. Examples include p.Arg502Ter classified with very strong pathogenic evidence and p.Leu103Pro interpreted through an ACMG-based workflow. | MAXO: genetic variant interpretation | ADGRG1 loss of function is a recognized disease mechanism, supporting pathogenic classification of truncating alleles. | (pqac-00000003, pqac-00000023, pqac-00000042, pqac-00000045) |
| Diagnostics | CNV/SV analysis | Exome-era workflows may include exome-based CNV/SV calling (e.g., CoNIFER, 3bCNV in the 2024 report) to avoid missing structural contributors when single-nucleotide testing is unrevealing. | MAXO: copy number variation analysis | Not a classic major mechanism for ADGRG1-BFPP based on retrieved evidence, but included in modern rare-disease diagnostic pipelines. | (pqac-00000042, pqac-00000044) |
| Diagnostics | Ancillary exclusion testing | In complex cases, clinicians have used chromosomal testing, fragile X/imprinting studies, mtDNA testing, metabolic screening, and muscle biopsy to exclude alternative diagnoses. | MAXO: metabolic testing; MAXO: muscle biopsy | Particularly useful when presentation mimics congenital muscular dystrophy/cobblestone complex or metabolic disease. | (pqac-00000003, pqac-00000045) |
| Differential diagnosis | Congenital CMV/HSV and other congenital infections | BFPP MRI may mimic congenital CMV or HSV because of polymicrogyria, ventriculomegaly, and white-matter abnormalities; infectious workup and molecular testing help avoid misdiagnosis. | MAXO: infectious disease differential diagnosis; MAXO: brain MRI | Important diagnostic pitfall emphasized in recent literature, especially where expert neuroradiology access is limited. | (pqac-00000010, pqac-00000043, pqac-00000044) |
| Differential diagnosis | Dystroglycanopathies / cobblestone muscular dystrophy | ADGRG1-related disease can present with early hypotonia and MRI overlap resembling cobblestone complex; normal muscle biopsy and the characteristic posterior fossa/brainstem pattern favor ADGRG1-related BFPP. | MAXO: muscle biopsy; MAXO: differential diagnosis | Early “pseudomyopathic” presentation is a recurring clinical trap. | (pqac-00000014, pqac-00000045) |
| Differential diagnosis | Other PMG subtypes / BGP / pachygyria-lissencephaly spectrum | Atypical ADGRG1 cases may lack the canonical gradient and instead show diffuse PMG or pachygyria/lissencephaly-like changes, requiring broad malformation-of-cortical-development differential diagnosis. | MAXO: exome sequencing; MAXO: neuroradiologic review | Broad genomic testing helps resolve overlap syndromes and possible multilocus disease. | (pqac-00000002, pqac-00000012, pqac-00000046) |
| Differential diagnosis | False reassurance from normal early MRI | One reported patient had a normal MRI in infancy despite later-confirmed ADGRG1-related disease; repeat imaging should be considered if clinical suspicion remains high. | MAXO: follow-up brain MRI | Normal early imaging does not exclude the diagnosis. | (pqac-00000043) |
| Management/Treatment | Antiseizure therapy | Seizure treatment is symptomatic and individualized. Reported medications include valproate (initially effective in one case), vigabatrin, levetiracetam, topiramate, clonazepam, and perampanel; many patients have refractory epilepsy. | MAXO: antiseizure medication therapy | No disease-modifying therapy identified in retrieved literature; seizure burden is often high and drug resistance common. | (pqac-00000003, pqac-00000041, pqac-00000044) |
| Management/Treatment | Developmental and supportive care | Real-world care typically includes multidisciplinary neurodevelopmental support for motor, cognitive, speech/language, feeding, and visual/oculomotor impairments, although disease-specific protocols are not detailed in the retrieved ADGRG1 papers. | MAXO: supportive care; MAXO: physical therapy; MAXO: speech therapy; MAXO: occupational therapy | Supportive management is inferred from the severe, lifelong neurodevelopmental phenotype and standard PMG care principles. | (pqac-00000009, pqac-00000013, pqac-00000015) |
| Management/Treatment | Longitudinal neurologic follow-up | Ongoing follow-up is needed for epilepsy evolution, ambulation, tone/pyramidal signs, cerebellar features, and developmental progress; some patients show regression with epileptic decompensation. | MAXO: neurologic follow-up | Clinical course is static structurally but functionally variable, especially with refractory epilepsy. | (pqac-00000041, pqac-00000046) |
| Management/Treatment | Clinical research implementation | Observational study NCT01488461 (“Phenotypic and Genotypic Studies in Congenital and Early Onset Ataxias”) posted 2011-12-08 and completed 2014-10 included sequencing of GPR56 in patients with suggestive congenital ataxia features. | MAXO: enrollment in observational study; MAXO: genetic testing | Illustrates real-world incorporation of GPR56/ADGRG1 testing into neurogenetics research/diagnostic pathways for cerebellar ataxia syndromes. | (pqac-00000017) |
| Prevention | Genetic counseling | Genetic counseling is strongly recommended for affected families, especially in consanguineous settings, to explain autosomal recessive inheritance, recurrence risk, testing options, and family planning. | MAXO: genetic counseling | Explicitly emphasized in the 2024 family report and supported by segregation-based diagnosis. | (pqac-00000042, pqac-00000043, pqac-00000044) |
| Prevention | Carrier testing / cascade testing | Once the familial ADGRG1 variant is known, targeted testing of parents, siblings, and extended relatives can identify carriers and clarify reproductive risk. | MAXO: carrier screening; MAXO: cascade genetic testing | Practical prevention strategy for rare recessive disease in extended families. | (pqac-00000041, pqac-00000042, pqac-00000045) |
| Prevention | Prenatal diagnosis / reproductive planning | Although not elaborated as formal protocols in all retrieved papers, family reports show direct reproductive utility of molecular diagnosis; one cited family used fetal testing in a subsequent pregnancy, and counseling papers explicitly frame genetic diagnosis as aiding future reproductive choices. | MAXO: prenatal genetic testing; MAXO: reproductive counseling; MAXO: preimplantation genetic testing | Appropriate once a familial pathogenic ADGRG1 variant is established. | (pqac-00000010, pqac-00000042, pqac-00000044) |
| Prevention | Consanguinity-informed risk assessment | In populations/families with consanguinity, earlier consideration of autosomal recessive BFPP and earlier exome/panel testing may shorten diagnostic delay and reduce recurrence through informed planning. | MAXO: risk assessment; MAXO: exome sequencing | Consanguinity is a prominent feature in many reported pedigrees. | (pqac-00000048, pqac-00000050, pqac-00000042) |


*Table: This table summarizes practical diagnostic workflows, common differential-diagnosis pitfalls, symptomatic management, and prevention/counseling strategies for ADGRG1-related bilateral frontoparietal polymicrogyria. It is useful for translating case-report and cohort evidence into a knowledge-base-ready clinical implementation view.*