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Somatic mosaicism of the PIK3CA gene identified in a Hungarian girl with macrodactyly and syndactyly.

Accepted version
Peer-reviewed

Repository DOI


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Authors

Tripolszki, Kornélia 
Knox, Rachel 
Parker, Victoria 
Farkas, Katalin 

Abstract

Isolated macrodactyly (OMIM 155500) belongs to a heterogeneous group of overgrowth syndromes. It is a congenital anomaly resulting in enlargement of all tissues localized to the terminal portions of a limb and caused by somatic mutations in the phosphatidylinositol 3-kinase catalytic alpha (PIK3CA, OMIM 171834) gene. Here we report a Hungarian girl with macrodactyly and syndactyly. Genetic screening at hotspots in the PIK3CA gene identified a mosaic mutation (c.1624G > A, p.Glu542Lys) in the affected tissue, but not in the peripheral blood. To date, this somatic mutation has been reported in eight patients affected by different forms of segmental overgrowth syndromes. Detailed analysis of the Hungarian child and previously reported cases suggests high phenotypic diversity associated with the p.Glu542Lys somatic mutation. The identification of the mutation provides a novel therapeutic modality for the affected patients: those who carry somatic mutations in the PIK3CA gene are potential recipients of a novel "repurposing" approach of rapamycin treatment.

Description

Keywords

Macrodactyly and syndactyly, Overgrowth syndromes, PIK3CA gene, Phenotypic diversity, Somatic mutation, Child, Preschool, Class I Phosphatidylinositol 3-Kinases, Female, Fingers, Humans, Hungary, Limb Deformities, Congenital, Mosaicism, Mutation, Phosphatidylinositol 3-Kinases, Syndactyly

Journal Title

Eur J Med Genet

Conference Name

Journal ISSN

1769-7212
1878-0849

Volume Title

59

Publisher

Elsevier BV
Sponsorship
This research was supported by the European Union and the State of Hungary, co-financed by the European Social Fund in the framework of TÁMOP-4.2.4.A/ 2-11/1-2012-0001 “National Excellence Program.” Nikoletta Nagy was also supported by the Hungarian Scientific Research Fund (OTKA) PD104782 grant.