Abstract |
Netherton syndrome (NS) is a rare, life-threatening ichthyosiform syndrome caused by recessive loss-of-function mutations in SPINK5 gene encoding lymphoepithelial Kazal-type-related inhibitor (LEKTI), a serine protease inhibitor expressed in the most differentiated epidermal layers and crucial for skin barrier function. We report the functional characterization of a previously unrecognized synonymous variant, c.891C>T (p.Cys297Cys), identified in the SPINK5 exon 11 of an NS patient. We demonstrated that the c.891C>T mutation is associated with abnormal pre-mRNA splicing and residual LEKTI expression in the patient's keratinocytes. Subsequent minigene splicing assays and in silico predictions confirmed the direct role of the synonymous mutation in inhibiting exon 11 inclusion by a mechanism that involves the activity of exonic regulatory sequences, namely splicing enhancer and silencer. However, this deleterious effect was not complete and a residual amount of normal mRNA and LEKTI protein could be detected, correlating with the relatively mild patient's phenotype. Our study represents the first identification of a disease-causing SPINK5 mutation that alters splicing without affecting canonical splice sites.
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Authors | Paola Fortugno, Fabiana Grosso, Giovanna Zambruno, Serena Pastore, Flavio Faletra, Daniele Castiglia |
Journal | Journal of human genetics
(J Hum Genet)
Vol. 57
Issue 5
Pg. 311-5
(May 2012)
ISSN: 1435-232X [Electronic] England |
PMID | 22377713
(Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Proteinase Inhibitory Proteins, Secretory
- SPINK5 protein, human
- Serine Peptidase Inhibitor Kazal-Type 5
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Topics |
- Cells, Cultured
- Child, Preschool
- Computational Biology
(methods)
- Enhancer Elements, Genetic
(genetics)
- Exons
(genetics)
- Female
- Genotype
- Humans
- Keratinocytes
- Mutation
- Netherton Syndrome
(genetics)
- Phenotype
- Proteinase Inhibitory Proteins, Secretory
(genetics)
- RNA Splicing
(genetics)
- Reverse Transcriptase Polymerase Chain Reaction
- Serine Peptidase Inhibitor Kazal-Type 5
- Silencer Elements, Transcriptional
(genetics)
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