Terminal osseous dysplasia with pigmentary defects and cardiomyopathy caused by a novel FLNA variant

Lynne Rumping*, Marja W. Wessels, Alex V. Postma, Joost van Schuppen, Marjon A. van Slegtenhorst, Jasper J. Saris, J. Peter van Tintelen, Stephen P. Robertson, Mariëlle Alders, Saskia M. Maas, Ronald H.Lekanne Deprez

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Terminal osseous dysplasia with pigmentary defects (TODPD), also known as digitocutaneous dysplasia, is one of the X-linked filaminopathies caused by a variety of FLNA-variants. TODPD is characterized by skeletal defects, skin fibromata and dysmorphic facial features. So far, only a single recurrent variant (c.5217G>A;p.Val1724_Thr1739del) in FLNA has found to be responsible for TODPD. We identified a novel c.5217+5G>C variant in FLNA in a female proband with skeletal defects, skin fibromata, interstitial lung disease, epilepsy, and restrictive cardiomyopathy. This variant causes mis-splicing of exon 31 predicting the production of a FLNA-protein with an in-frame-deletion of 16 residues identical to the miss-splicing-effect of the recurrent TODPD c.5217G>A variant. This mis-spliced transcript was explicitly detected in heart tissue, but was absent from blood, skin, and lung. X-inactivation analyses showed extreme skewing with almost complete inactivation of the mutated allele (>90%) in these tissues, except for heart. The mother of the proband, who also has fibromata and skeletal abnormalities, is also carrier of the FLNA-variant and was diagnosed with noncompaction cardiomyopathy after cardiac screening. No other relevant variants in cardiomyopathy-related genes were found. Here we describe a novel variant in FLNA (c.5217+5G>C) as the second pathogenic variant responsible for TODPD. Cardiomyopathy has not been described as a phenotypic feature of TODPD before.

Original languageEnglish
Pages (from-to)3814-3820
Number of pages7
JournalAmerican Journal of Medical Genetics, Part A
Volume185
Issue number12
Early online date13 Jul 2021
DOIs
Publication statusPublished - Dec 2021

Bibliographical note

Funding Information:
We are grateful for the contribution of the patient's family to this study. We would like to thank Marloes Willemsen, Maureen Rahanra and Naomi Donner (Academic Medical Centre Amsterdam) for their great technical assistance. We thank Emma Wade and Kaya Fukushima (University of Otago, New Zealand) for helpful discussions. This project has not been funded. The parents of the proband have given informed consent for publication of the medical data and pictures.

Publisher Copyright:
© 2021 The Authors. American Journal of Medical Genetics Part A published by Wiley Periodicals LLC.

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