| Category | Details | Key evidence (with PMID if explicitly available in text; otherwise include DOI and year) | Notes |
|---|---|---|---|
| Disease name / identifiers | ATR-X syndrome; alpha-thalassemia X-linked intellectual disability syndrome; OMIM #301040. Related allelic/overlapping designation: MRXHF1, OMIM #309580. Orphanet identifier reported as ORPHA:847 in a 2024 review. | OMIM #301040 noted in multiple case/review sources; doi:10.3389/fped.2024.1460658 (2024); doi:10.1186/s12887-024-05088-0 (2024); doi:10.3389/fped.2022.834087 (2022); ORPHA:847 noted in doi:10.1051/medsci/2024181 (2024) (pqac-00000012, pqac-00000002, pqac-00000003) | ICD/MeSH/MONDO identifiers were not directly available in retrieved context. |
| Common synonyms | Alpha-thalassemia/mental retardation syndrome, X-linked; alpha-thalassemia X-linked intellectual disability syndrome; ATR-X syndrome. | doi:10.3389/fped.2022.834087 (2022); doi:10.3389/fped.2024.1460658 (2024) (pqac-00000003, pqac-00000012) | “Mental retardation” appears in legacy nomenclature but is outdated in current clinical usage. |
| Resource type | Disease information is derived mainly from aggregated disease-level resources/reviews and published patient case series/cohorts; recent reports often use WES/WGS-confirmed individual patients. | doi:10.1186/s12887-024-05088-0 (2024); doi:10.3390/genes13101792 (2022) (pqac-00000004, pqac-00000008) | Not primarily EHR-derived in the retrieved literature. |
| Inheritance / sex effect | X-linked inheritance; typically affects hemizygous males; females are often asymptomatic or milder because of skewed X-chromosome inactivation. | doi:10.3389/fmolb.2024.1434398 (2024); doi:10.3389/fped.2022.834087 (2022) (pqac-00000005, pqac-00000003) | Carrier mothers may show skewed XCI; counseling is important for family planning. |
| Causal gene | ATRX (OMIM *300032), located at Xq13-q21/Xq21.1; chromatin-remodeling ATPase of the SNF2 family; 35 exons; protein length 2,492 aa. | doi:10.3389/fped.2022.834087 (2022); doi:10.1101/2023.01.25.525394 (2023) (pqac-00000003, pqac-00000001) | Core domains: N-terminal ADD domain and C-terminal helicase/ATPase domain. |
| Variant spectrum | Predominantly hypomorphic germline variants; missense most common; also frameshift, nonsense, splice-site, and small in-frame indels. Variants cluster in ADD and helicase-like domains. In one 2024 review set: 35 missense, 7 frameshift, 4 nonsense, 5 splicing variants among 63 reviewed patients/50 pathogenic variants. | doi:10.1186/s12887-024-05088-0 (2024); doi:10.1101/2023.01.25.525394 (2023) (pqac-00000004, pqac-00000001) | Germline disease alleles are typically partial loss-of-function rather than null. |
| Prevalence / incidence | Estimated prevalence ~1/30,000–1/40,000 male newborns in one 2024 source; another review cites incidence <1/100,000 live-born males; broader rare-disease estimate <1–9/1,000,000. More than 130 families and >200 affected individuals/cases have been described. | doi:10.1186/s12887-024-05088-0 (2024); doi:10.3389/fped.2024.1460658 (2024); doi:10.3389/fgene.2020.00885 (2020) (pqac-00000009, pqac-00000012, pqac-00000010) | Estimates vary by source and likely reflect underdiagnosis, especially of mild/atypical cases. |
| Core phenotype | Severe-to-profound intellectual/developmental disability is the constant feature; facial dysmorphism, hypotonia, skeletal abnormalities, genital anomalies, and hematologic abnormalities are typical. | doi:10.3389/fmolb.2024.1434398 (2024); doi:10.3389/fgene.2020.00885 (2020) (pqac-00000005, pqac-00000010) | Expressive language is often markedly impaired; some patients lack alpha-thalassemia. |
| Alpha-thalassemia / hematology | Alpha-thalassemia or HbH inclusions occur in about 75% of affected individuals, but may be absent; severity of neurodevelopmental impairment does not correlate well with degree of alpha-thalassemia. | doi:10.3389/fped.2024.1460658 (2024); doi:10.3389/fped.2021.811812 (2022); doi:10.1101/2023.01.25.525394 (2023) (pqac-00000012, pqac-00000001) | Absence of alpha-thalassemia does not exclude ATRX-related disease. |
| Phenotype frequencies (selected literature) | Review data cited in 2022 source: profound ID 100%, characteristic facial features 100%, microcephaly ~75%, genital abnormalities ~63–67%, neonatal hypotonia 40%, short stature 50%, gut dysmotility ~36%, seizures ~36%, renal/urinary abnormalities ~25%. Italian 17-patient cohort: microcephaly 12/15 (80%), short stature 11/17 (64.5%), hand/foot anomalies 11/17 (64.5%), scoliosis/kyphosis 10/17 (59%), neuroimaging signs 10/17 (59%), obstructive sleep apnea 4/17 (23.5%), dysthyroidism 3/17 (17.5%), osteoporosis 3/17 (17.5%). | doi:10.3389/fped.2022.834087 (2022); doi:10.3390/genes13101792 (2022) (pqac-00000006, pqac-00000008) | Frequencies vary by cohort composition, ascertainment, and whether mild ATRX-related cases are included. |
| Genotype–phenotype highlights | Frameshift/nonsense variants may show higher rates of epilepsy and congenital anomalies; ADD-domain variants are associated with more severe psychomotor/language impairment; C-terminal frameshifts may confer more urogenital defects. | doi:10.1186/s12887-024-05088-0 (2024); doi:10.3389/fped.2022.834087 (2022) (pqac-00000004, pqac-00000006) | Current reviews caution that many domain-based predictions remain imperfect and not fully prognostic. |
| Natural history / onset | Congenital or early-infantile onset with global developmental delay, hypotonia, feeding/GI issues, and delayed motor/language milestones; aspiration is a recognized cause of early childhood death. Prenatal decreased fetal movements and preterm birth (~1/3 in one cohort) have been reported. | doi:10.3389/fped.2024.1460658 (2024); doi:10.3390/genes13101792 (2022) (pqac-00000012, pqac-00000008) | Lifelong neurodevelopmental disorder with multisystem complications. |
| Diagnostic genetics | Molecular confirmation relies on ATRX variant detection by WES/WGS or targeted sequencing, typically with Sanger confirmation; RT-PCR may confirm splice effects; X-inactivation studies can support interpretation in carrier females. | doi:10.3389/fped.2022.834087 (2022); doi:10.1186/s12887-024-05088-0 (2024) (pqac-00000003, pqac-00000004) | Modern NGS is expanding detection of atypical cases lacking classic hematologic features. |
| Epigenetic / biomarker diagnostics | Peripheral-blood DNA methylation “episignature” is highly specific for ATR-X syndrome; demonstrated in 18 patients vs 210 controls, with hierarchical clustering separating cases and controls; significant loci clustered in pericentromeric/telomeric regions. | doi:10.1186/s13072-017-0118-4 (2017) (pqac-00000014, pqac-00000015) | Useful as a supportive diagnostic biomarker, especially for variants of uncertain significance. |
| Management highlights | No disease-modifying standard therapy identified in retrieved clinical literature; management is supportive and multidisciplinary. Speech/occupational therapy may help some functional issues (e.g., drooling), though cognitive gains may be limited. | doi:10.1186/s12887-024-05088-0 (2024) (pqac-00000004) | Typical care includes developmental, neurologic, GI, nutrition, and urogenital management. |
| GI management / real-world implementation | GI complications are common and clinically important. Recent case-based evidence suggests pyridostigmine can improve pediatric GI dysmotility when first-line measures fail; reported doses varied, and one case had full symptom resolution after 1 year. | doi:10.3389/fped.2024.1460658 (2024) (pqac-00000011, pqac-00000012) | Evidence remains low-level (case report/literature review); optimal dosing and long-term safety are uncertain. |
| Mechanistic / translational development | 2023 mouse work linked ATRX loss to myelination defects and oligodendrocyte progenitor differentiation; thyroxine partially rescued myelination deficits in male mice. | doi:10.1038/s41467-023-42752-y (2023) (pqac-00000008) | Promising mechanistic insight, but not established human therapy for ATR-X syndrome. |
| Clinical trials | No disease-specific interventional clinical trials were identified in the retrieved search context. | Clinical trials search in retrieved context (2024 search) (pqac-00000000) | Current care is largely individualized supportive management and complication prevention. |


*Table: This table summarizes the main identifiers, inheritance and molecular basis, prevalence estimates, phenotype frequencies, and current diagnostic and management highlights for ATR-X syndrome. It is designed as a compact evidence-backed reference for knowledge-base curation.*