NICOLA JUAN PABLO
Congresos y reuniones científicas
Título:
Silent but not harmless: A synonymous SLC5A5 gene variant leading to dyshormonogenic congenital hypothyroidism
Autor/es:
GEYSELS, RC; BERNAL BARQUERO, CE; MARTIN, M; PEYRET, V; NOCENT, M; SOBRERO, G; MUÑOZ, L; SIGNORINO, M; TESTA, G; MIRAS, M; MASINI-REPISO, AM; NICOLA, JP
Reunión:
Congreso; XVIII Latin American Thyroid Congress; 2021
Institución organizadora:
Latin American Thyroid Society
Resumen:
Iodide transport defect (ITD) is an autosomal recessive disorder whose hallmark is the inability of the thyroid follicular
cell to actively accumulate iodide. ITD is an uncommon cause of dyshormonogenetic congenital hypothyroidism that results from
inactivating mutations in the sodium iodide symporter (NIS)-coding gene SLC5A5. Phonotypical manifestations include low to absent
thyroid iodide accumulation and, if untreated, variable degree of hypothyroidism, goiter, and even mental retardation. Objective: To
investigate the presence of pathogenic variant in SLC5A5 gene in five unrelated patients with low to absent iodide accumulation in
a normally located thyroid gland. Methods: SLC5A5 gene was sequenced. In silico and functional in vitro characterization of the
SLC5A5 variants was performed using splicing prediction tools and splicing minigene reporter assay, respectively. Results: Patients’
SLC5A5 gene sequencing revealed the homozygous synonymous variants c.1,326A>C (exon 11) and c.1,626C>T (exon 13) in
two patients, whereas no variants were identified in the remaining patients. The variant c.1,326A>C (rs73520743) showed an allele
frequency of 0.001103 in the European (non-Finnish) population, while c.1,626C>T (rs45602038) was 0.02997, according to The
Genome Aggregation Database. In silico analysis assessing the effect of variants on splicing regulatory elements using the softwares
ESEfinder and HExoSplice revealed that c.1326A>C is potentially deleterious for normal NIS pre-mRNA splicing. The variant
c.1326A>C was predicted to lie at a potential exonic splicing enhancer (ESE) motif using ESEfinder software. The motif carrying
the variant c.1326A>C exhibited a decrease in the splicing regulatory protein SRSF5 score to below the threshold level. In addition,
the analysis using HExoSplice software revealed that the variant c.1326A>C causes a significant negative effect on the exonic splicing
regulatory (ESR) sequence (ΔtESRseq = -0.5932) whose identity overlaps with the ESEfinder-prediced SRSF5 binding site. Splicing
pSPL3-based minigene assay in HeLa cells revealed that c.1326A>C causes exon 11 skipping during NIS pre-mRNA splicing leading
to the in-frame NIS deletion variant p.G415_P443del. Conclusions: We identified the exonic synonymous c.1326A>C SLC5A5
gene variant causing aberrant NIS pre-mRNA splicing, thus expanding the mutational landscape in the SLC5A5 gene leading to
dyshormonogenic congenital hypothyroidism.
cell to actively accumulate iodide. ITD is an uncommon cause of dyshormonogenetic congenital hypothyroidism that results from
inactivating mutations in the sodium iodide symporter (NIS)-coding gene SLC5A5. Phonotypical manifestations include low to absent
thyroid iodide accumulation and, if untreated, variable degree of hypothyroidism, goiter, and even mental retardation. Objective: To
investigate the presence of pathogenic variant in SLC5A5 gene in five unrelated patients with low to absent iodide accumulation in
a normally located thyroid gland. Methods: SLC5A5 gene was sequenced. In silico and functional in vitro characterization of the
SLC5A5 variants was performed using splicing prediction tools and splicing minigene reporter assay, respectively. Results: Patients’
SLC5A5 gene sequencing revealed the homozygous synonymous variants c.1,326A>C (exon 11) and c.1,626C>T (exon 13) in
two patients, whereas no variants were identified in the remaining patients. The variant c.1,326A>C (rs73520743) showed an allele
frequency of 0.001103 in the European (non-Finnish) population, while c.1,626C>T (rs45602038) was 0.02997, according to The
Genome Aggregation Database. In silico analysis assessing the effect of variants on splicing regulatory elements using the softwares
ESEfinder and HExoSplice revealed that c.1326A>C is potentially deleterious for normal NIS pre-mRNA splicing. The variant
c.1326A>C was predicted to lie at a potential exonic splicing enhancer (ESE) motif using ESEfinder software. The motif carrying
the variant c.1326A>C exhibited a decrease in the splicing regulatory protein SRSF5 score to below the threshold level. In addition,
the analysis using HExoSplice software revealed that the variant c.1326A>C causes a significant negative effect on the exonic splicing
regulatory (ESR) sequence (ΔtESRseq = -0.5932) whose identity overlaps with the ESEfinder-prediced SRSF5 binding site. Splicing
pSPL3-based minigene assay in HeLa cells revealed that c.1326A>C causes exon 11 skipping during NIS pre-mRNA splicing leading
to the in-frame NIS deletion variant p.G415_P443del. Conclusions: We identified the exonic synonymous c.1326A>C SLC5A5
gene variant causing aberrant NIS pre-mRNA splicing, thus expanding the mutational landscape in the SLC5A5 gene leading to
dyshormonogenic congenital hypothyroidism.
