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Diagnosis and clinical presentation of two individuals with a rare TCF20 pathogenic variant
  1. Michelle Robyn Schneeweiss1,
  2. Breanne Dale2 and
  3. Resham Ejaz3,4
  1. 1Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
  2. 2Genetics and Metabolics Clinic, McMaster Children's Hospital, Hamilton, Ontario, Canada
  3. 3Division of Genetics, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
  4. 4Department of Pediatrics, McMaster Children's Hospital, Hamilton, Ontario, Canada
  1. Correspondence to Dr Resham Ejaz; ejazr{at}


TCF20-associated neurodevelopmental disorder (TAND) is a rare and phenotypically variable genetic condition. Common features include intellectual disability, neurobehavioural concerns, postnatal tall stature and hypotonia.

Two unrelated early adolescent males were referred to genetics for assessment of developmental delay. The first male of Caucasian descent had a history of autism spectrum disorder (ASD), mitral valve prolapse and subtle craniofacial dysmorphisms. The second male of Somali descent had a history of intellectual disability, thick corpus callosum and ASD. Whole-exome sequencing revealed a pathogenic variant in TCF20 in both individuals. Further testing revealed that the former individual’s mother was mosaic for the TCF20 pathogenic variant.

We report two individuals with TCF20 pathogenic variants presenting with unique findings, including thick corpus callosum, family history of mosaicism and cardiac anomalies. These examples expand the TAND phenotype, describe associated dysmorphism in a minority group and highlight the importance of rare disease research.

  • Genetic screening / counselling
  • Developmental paediatrocs
  • Paediatrics
  • Medical education

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  • Contributors MRS is an MD candidate who collected the data on the patients’ presentation, and drafted the initial case report summarising the presentation and findings. MRS also liaised with patients to gather more information on their presentation and treatment outcomes. MRS was also responsible for gaining parental/patient consent and perspectives in writing the case reports. BD was the genetic counsellor involved in the care of the patients in question and RE was the medical geneticist. Both BD and RE were involved clinically in diagnosing the patients' conditions and providing treatment/counselling after a diagnosis was confirmed. Both BD and RE oversaw MRS in her role of drafting the initial report and working with patients/parents to understand their perspectives and obtain consent. Both BD and RE revised the draft paper into the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.