| Domain | Finding (with numbers) | Population/Study | Year | URL |
|---|---|---|---|---|
| Genetic lesion | Canonical WS/WBS lesion is a hemizygous 7q11.23 microdeletion of ~1.6 Mb deleting ~25 genes; representative genes include **ELN, LIMK1, GTF2I, GTF2IRD1, DNAJC30, FZD9, STX1A** (pqac-00000010, pqac-00000012) | Neurodevelopmental/imaging and case-report literature on WS/WBS | 2023–2024 | https://doi.org/10.1186/s11689-023-09493-x ; https://doi.org/10.33448/rsd-v13i5.45910 |
| Genetic lesion | Prenatal cohort observed deletion sizes **1.43–1.78 Mb** encompassing **29 OMIM genes**, including **ELN, DNAJC30, GTF2IRD1, GTF2I** (pqac-00000008) | 7 fetuses with 7q11.23 deletion identified by SNP-array | 2024 | https://doi.org/10.1186/s12884-024-06920-2 |
| Epidemiology / incidence | Frequently cited incidence/prevalence estimate: **~1 in 7,500 live births/newborns** for WS/WBS (pqac-00000001, pqac-00000008) | Developmental cohort/review statements and prenatal review | 2023–2024 | https://doi.org/10.55730/1300-0144.5701 ; https://doi.org/10.1186/s12884-024-06920-2 |
| Phenotype frequencies: broad pediatric cohort | In **231 Chinese children**: facial dysmorphism **100.0%**; neurodevelopmental disorder **91.8%**; hoarseness **87.4%**; cardiovascular anomalies **85.7%**; inguinal hernia **47.2%**; short stature **46.9%**; hypercalciuria **29.1%**; subclinical hypothyroidism **26.4%**; hypercalcemia **9.1%**; hypothyroidism **7.4%** (pqac-00000015) | Single-center retrospective cohort of 231 children with WS in China | 2022 | https://doi.org/10.1002/mgg3.2069 |
| Phenotype frequencies: adaptive/developmental profile | In **12 genetically confirmed patients**: delayed fine/gross motor domains in **6/12**, language delay in **4/12**, and delays in all domains in **2/12**; mean age at review **54.6 ± 32.5 months**, first developmental clinic presentation **15.0 ± 11.5 months** (pqac-00000001) | Developmental-behavioral pediatric cohort | 2023 | https://doi.org/10.55730/1300-0144.5701 |
| Phenotype frequencies: ophthalmic | In **57 WBS patients**: stellate iris **30/57 (52.6%)**; retinal arteriolar tortuosity **51/57 (89.5%)**; axial length <20.5 mm in **24 eyes (21.8%)**; axial length 20.5–22.0 mm in **38 eyes (34.5%)**; hypopigmented retinal deposits **OD 29/57, OS 27/57**; broad foveal pit contour **OD 44/55, OS 42/51** (pqac-00000016) | NIH deep-phenotyping ophthalmic study | 2023 | https://doi.org/10.1136/bjophthalmol-2022-321103 |
| Phenotype frequencies: ophthalmic (additional quantitative data) | In the same ophthalmic cohort: strabismus **17/57 (29.8%)**; 10 esotropia, 7 exotropia; prior strabismus surgery **15**; amblyopia **8**; BCVA ranged **20/20 to 20/80 OD** and **20/20 to 20/400 OS** (pqac-00000018) | NIH deep-phenotyping ophthalmic study | 2023 | https://doi.org/10.1136/bjophthalmol-2022-321103 |
| Phenotype frequencies: prenatal ultrasound | In **7 deletion fetuses**, **6/7** had ultrasound abnormalities; **3/7** had intrauterine growth restriction; **4/7** had cardiovascular abnormalities, including **2 VSD**, **1 aortic narrowing**, **1 supravalvular pulmonary stenosis** (pqac-00000017) | Single-center prenatal SNP-array cohort | 2024 | https://doi.org/10.1186/s12884-024-06920-2 |
| Diagnostics / confirmation | Historically **FISH** confirmed the 7q11.23 deletion, but expert review notes FISH has been superseded by **chromosomal microarray / array CGH** for routine confirmation of WS (pqac-00000025) | Expert disease primer / management review | 2021 | https://doi.org/10.1038/s41572-021-00276-z |
| Diagnostics / confirmation | Developmental cohort states **99% of patients** have a submicroscopic deletion detectable by **FISH** (pqac-00000001) | Pediatric developmental cohort summary | 2023 | https://doi.org/10.55730/1300-0144.5701 |
| Diagnostics / SVAS when WS excluded | In WS-negative SVAS cohort (**n=61 with testing data available**): **CMA** performed in **44/61** and was nondiagnostic; sequencing performed in **47/61** with overall diagnostic yield **29/47 (62%)**; **ELN sequencing** diagnostic in **20/39 (51%)** (pqac-00000021) | Retrospective cohort of patients with SVAS after negative WS evaluation | 2024 | https://doi.org/10.1161/jaha.123.034048 |
| Diagnostics / SVAS algorithmic yield | Same study reports **0% CMA diagnostic yield** and **62% sequencing diagnostic yield**; among **ELN single-gene sequencing**, **17/22 (77%)** were positive, supporting **ELN-first** or multigene panel/exome after negative WS testing (pqac-00000019, pqac-00000022, pqac-00000023) | Retrospective SVAS cohort and proposed testing algorithm | 2024 | https://doi.org/10.1161/jaha.123.034048 |
| Clinical trials | **NCT06087757** clemastine Phase 2 trial: **30 participants**, ages **6–30**, ACTIVE_NOT_RECRUITING; primary completion estimated **May 2026** (pqac-00000027) | Clemastine Treatment in Individuals With Williams Syndrome | 2024 | https://clinicaltrials.gov/study/NCT06087757 |
| Clinical trials | **NCT00876200** minoxidil trial: **21 participants**, Phase 2, COMPLETED; targeted arterial wall hypertrophy in children with Williams-Beuren syndrome (pqac-00000029) | Efficacy of Minoxidil in Children With Williams-Beuren Syndrome | 2009 / linked publication 2019 | https://clinicaltrials.gov/study/NCT00876200 |
| Clinical trials | **NCT03827525** CBT/anxiety study: estimated enrollment **5 adults**; **9 CBT sessions** over ~**5 months** with follow-up to month **8** (pqac-00000034) | Cognitive and Behavioral Therapy of Anxiety in Williams Syndrome | 2019 | https://clinicaltrials.gov/study/NCT03827525 |


*Table: This table compiles key numeric findings for Williams syndrome / Williams-Beuren syndrome across genetics, epidemiology, phenotype frequencies, diagnostic yield, and active or completed clinical trials. It is designed as a quick-reference evidence summary for knowledge-base curation.*