Footnotes

• Correction notice This article has been corrected since it was published online first. An error in the title has been corrected, and the contributors statement has been updated.

• Contributors MA was a principal investigator and contributed to study design, pedigree construction and writing of the manuscript; AS read and commented on the ultrastructural changes in biopsy specimens; AM correlated the data in protein analysis and electron microscopy; TB contributed to the review of literature and collection of samples; MP contributed to molecular diagnosis and revised the manuscript.

• Funding The authors declare that they have not received any funds from any organising bodies in this work.

• Competing interests None.

• Patient consent Obtained.

• Ethics approval Mansoura University Children's Hospital Ethical Committee.

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