{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,19]],"date-time":"2026-05-19T13:13:31Z","timestamp":1779196411496,"version":"3.51.4"},"reference-count":15,"publisher":"BMJ","issue":"5","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,5,1]]},"published-print":{"date-parts":[[2026,5]]},"abstract":"<jats:p>\n                    <jats:italic>GNB1<\/jats:italic>\n                    -related neurodevelopmental disorder is a rare developmental encephalopathy caused by pathogenic variants in\n                    <jats:italic>GNB1<\/jats:italic>\n                    . The disorder presents with early-onset developmental delay, hypotonia, movement disorders, seizures and\/or epilepsy and varied electroencephalographic (EEG) findings, which may occur even in the absence of seizures.\n                  <\/jats:p>\n                  <jats:p>\n                    We report a male toddler with early-onset global developmental delay, hypotonia, dysmorphic features, bilateral sensorineural hearing loss, nystagmus, transient neonatal focal seizures and emerging EEG findings. Genetic testing identified a pathogenic\n                    <jats:italic>GNB1<\/jats:italic>\n                    missense variant NM_002074.5:c239T&gt;A (p.Ile80Asn) inherited from an asymptomatic father with mosaicism.\n                  <\/jats:p>\n                  <jats:p>This case illustrates the clinical variability of GNB1 encephalopathy, expands the spectrum of reported inheritance patterns and highlights the importance of early genetic testing of infants with developmental delay and pathological EEG patterns. Recognition of the electroclinical patterns is essential for early diagnosis, genetic counselling and multidisciplinary management. The future expansion of longitudinal clinical and EEG data will be essential for prognosis and possible future therapeutic approaches.<\/jats:p>","DOI":"10.1136\/bcr-2026-272194","type":"journal-article","created":{"date-parts":[[2026,5,19]],"date-time":"2026-05-19T12:55:30Z","timestamp":1779195330000},"page":"e272194","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["<i>GNB1<\/i>\n                    -related neurodevelopmental disorder due to a pathogenic exon 6 variant NM_002074.5:c239T&gt;A (p.Ile80Asn) inherited from an asymptomatic father with mosaicism"],"prefix":"10.1136","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4882-1524","authenticated-orcid":false,"given":"Learta","family":"Alili Ademi","sequence":"first","affiliation":[{"name":"Neurology, University Clinic for Children\u2019s Diseases, Skopje, North Macedonia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"E","family":"Sukarova-Angelovska","sequence":"additional","affiliation":[{"name":"Genetics, University Clinic for Children\u2019s Diseases, Skopje, North Macedonia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Danilo","family":"Nonkulovski","sequence":"additional","affiliation":[{"name":"Neurology, University Clinic for Children\u2019s Diseases, Skopje, North Macedonia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Blerim","family":"Ademi","sequence":"additional","affiliation":[{"name":"University Clinic for Children\u2019s Diseases, Skopje, North Macedonia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2026,5,19]]},"reference":[{"key":"2026051905551509000_19.5.e272194.1","unstructured":"National Center for Biotechnology Information (NCBI) . GNB1 gene (gene ID: 2782). Available: https:\/\/www.ncbi.nlm.nih.gov\/gene\/2782 [Accessed 6 Apr 2026]."},{"key":"2026051905551509000_19.5.e272194.2","unstructured":"National Center for Biotechnology Information (NCBI) . GNB1 transcript variant 1 (NM_002074.5) and protein (NP_002065.1). Available: https:\/\/www.ncbi.nlm.nih.gov\/nuccore\/NM_002074.5 [Accessed 6 Apr 2026]."},{"key":"2026051905551509000_19.5.e272194.3","doi-asserted-by":"publisher","DOI":"10.1007\/s00018-008-8006-5"},{"key":"2026051905551509000_19.5.e272194.4","doi-asserted-by":"publisher","DOI":"10.1152\/physrev.00003.2005"},{"key":"2026051905551509000_19.5.e272194.5","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajhg.2016.03.011"},{"key":"2026051905551509000_19.5.e272194.6","first-page":"610","article-title":"Refining the phenotype associated with GNB1 mutations: developmental delay, movement disorders, and epilepsy","volume":"39","author":"Hemati","year":"2018","journal-title":"Hum Mutat"},{"key":"2026051905551509000_19.5.e272194.7","first-page":"758","article-title":"Expanding the clinical and molecular spectrum of GNB1-related neurodevelopmental disorder","volume":"179","author":"Jones","year":"2019","journal-title":"Am J Med Genet A"},{"key":"2026051905551509000_19.5.e272194.8","first-page":"1173","article-title":"Phenotypic spectrum of GNB1 encephalopathy: epilepsy, movement disorders, and genotype\u2013phenotype correlations","volume":"61","author":"Endo","year":"2020","journal-title":"Epilepsia"},{"key":"2026051905551509000_19.5.e272194.9","doi-asserted-by":"publisher","DOI":"10.1002\/ajmg.a.40472"},{"key":"2026051905551509000_19.5.e272194.10","first-page":"165","article-title":"Novel GNB1 de novo mutation in a patient with neurodevelopmental disorder and cutaneous mastocytosis","volume":"6","author":"Wang","year":"2017","journal-title":"J Pediatr Genet"},{"key":"2026051905551509000_19.5.e272194.11","first-page":"564","article-title":"Biased G protein signaling in GNB1-related movement disorders and developmental delay","volume":"82","author":"Lohmann","year":"2017","journal-title":"Ann Neurol"},{"key":"2026051905551509000_19.5.e272194.12","doi-asserted-by":"crossref","DOI":"10.3389\/fneur.2021.735549","article-title":"Case Report: A Novel GNB1 Mutation Causes Global Developmental Delay With Intellectual Disability and Behavioral Disorders","volume":"12","author":"Da Silva","year":"2021","journal-title":"Front Neurol"},{"key":"2026051905551509000_19.5.e272194.13","first-page":"589","article-title":"GNB1 Encephalopathy: Clinical Case Report and Literature Review","volume":"60","author":"Nasvytis","year":"2024","journal-title":"Med Bogota Colomb"},{"key":"2026051905551509000_19.5.e272194.14","doi-asserted-by":"crossref","first-page":"462","DOI":"10.1016\/j.braindev.2023.06.005","article-title":"Atypical clinical course in two patients with GNB1 variants who developed acute encephalopathy","volume":"45","author":"Tsuji","year":"2023","journal-title":"Brain Dev"},{"key":"2026051905551509000_19.5.e272194.15","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1007\/s42000-024-00615-1","article-title":"The possible association of two novel heterozygous GNB1 variants with obesity and metabolic disorders","volume":"24","author":"Karantza","year":"2025","journal-title":"Hormones (Athens)"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2026-272194","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,19]],"date-time":"2026-05-19T12:55:34Z","timestamp":1779195334000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2026-272194"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5]]},"references-count":15,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026,5,19]]},"published-print":{"date-parts":[[2026,5]]}},"alternative-id":["10.1136\/bcr-2026-272194"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2026-272194","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5]]}}}