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Iris anomalies and the incidence of ACTA2 mutation
  1. Kenneth J Taubenslag,
  2. Hannah L Scanga,
  3. Jennifer Huey,
  4. Jennifer Lee,
  5. Anagha Medsinge,
  6. Christin L Sylvester,
  7. Kenneth P Cheng,
  8. Ken K Nischal
  1. UPMC Eye Center, Children’s Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
  1. Correspondence to Dr Ken K Nischal, UPMC Eye Center, Children’s Hospital of Pittsburgh of UPMC, Floor 5, 4401 Penn Avenue, Pittsburgh, PA 15224, USA; nischalkk{at}upmc.edu

Abstract

Background Central cysts of the iris pigment epithelium, or iris flocculi, are frequently reported in the literature in association with thoracic aortic aneurysm and dissection due to smooth muscle alpha-actin 2 (ACTA2) mutations. Children with ACTA2 mutations may also present with congenital mydriasis. We report our experience regarding the frequency of ACTA2 mutation in children with the above iris anomalies.

Methods This is a retrospective, consecutive case series of all children presenting for iris flocculi or congenital mydriasis at a single tertiary centre from October 2012 to December 2016.

Results 13 children with iris flocculi and 3 with congenital mydriasis presented during the study period. 10 children with iris flocculi completed genetic testing, and none were positive for ACTA2 mutation. All children with congenital mydriasis presented with a multisystem smooth muscle dysfunction syndrome; two of these three children tested positive for missense R179 ACTA2 mutations.

Conclusions In this series, ACTA2 mutation or copy number variation was not detected in children presenting for iris flocculi, whereas congenital mydriasis was associated with R179 mutation in both cases that tested positive for ACTA2 mutation. The case of congenital mydriasis without typical cardiac features of the R179 ACTA2 phenotype or intracranial vasculopathy was negative for ACTA2 mutation. While all children presenting with these iris anomalies should be offered a genetic evaluation, incidence data should inform genetic counselling, particularly in the absence of a family history of aneurysm or sudden death, or systemic signs of smooth muscle dysfunction.

  • iris flocculi
  • congenital mydriasis
  • ACTA2
  • pigment epithelial cyst
  • thoracic aortic aneurysm and dissection
  • multi-system smooth muscle dysfunction syndrome

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Footnotes

  • Funding Supported in part by a Research to Prevent Blindness Unrestricted Grant to the UPMC Eye Center. The sponsor or funding organisation had no role in the design or conduct of this research.

  • Competing interests None declared.

  • Ethics approval The protocol, compliant with the Health Insurance Portability and Accountability Act and adherent to the Declaration of Helsinki, was approved by the Institutional Review Board of the University of Pittsburgh.

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

  • Presented at A portion of this work was presented at the International Society for Genetic Eye Diseases and Retinoblastoma (ISGEDR) Annual Meeting, Leeds, UK, 14–16 September 2017.

  • Patient consent Not required.

  • Contributors KJT and KKN had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of data analysis. Study concept and design: KJT, HLS and KKN. Acquisition, analysis or interpretation of data: all authors. Drafting of the manuscript: KJT and KKN. Critical revision of the manuscript for important intellectual content: all authors. Administrative, technical or material support: all authors. Study supervision: KKN.

  • Data sharing statement Additional unpublished data may be available from the corresponding author.

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