NEW TECHNIQUES OF MOLECULAR BIOLOGY FOR THE DIAGNOSIS OF IODIDE ORGANIFICATION DEFECTS

MARICEL MOLINA; FIORELLA BELFORTE; EZEQUIELA ADROVER

Congreso; Reunión conjunta de SAIC SAI SAFIS 2018; 2018

Iodide Organification defects (IOD) represent 10% of cases of congenitalhypothyroidism (CH) being the main genes affected that ofTPO and DUOX2. From eight patients with clinical and biochemicalcriteria suggestive with CH associated with IOD, TPO and DUOX2genes were analyzed (Patients 1-8). In principle sequencing by theSanger technique was carried out. In those cases in which a singlemutation was identified in the TPO gene, NGS technique wasused. A custom panel targeting 8 genes associated with dishormonogenesis(TPO, IYD, SLC26A4, TG, DUOX2, DUOXA2, TSHR,SLC5A5) has been designed in order to amplify all exons and exon-intron of the respective genes by multiplex PCR. Sequencing ofthese amplicon libraries was carried out by using the Miseq Iluminaplatform. 4 novel mutations have been identied (two en TPO, onein TG and 1 in DUOX2). The heterozygous compound to the novelmutation c.2695delC, p.Q899Qfs*21 and the c.2895_2898del-GTTC, p.S965Sfs*30 was identified in the DUOX2 gene in Patient1. Sequencing analysis of TPO gene revealed the following inactivatingmutations: c.1993C>T, p.R665W and c.2395G>A, p.E799Kin Patient 2; c.1186_1187insGGCC, p.R396Rfs*77 and c.1682C>T,p.T561M in Patient 3; c.1496C>T, p.P499L and c.1682C>T, p.T561Min Patient 4, c.920A>C, p.N307T (novel) and c.1727C>A, p.A576Ein Patient 5; c.1186_1187insGGCC, p.R396Rfs*77 and c.1727C>A,p.A576E in Patient 6. In addition to mutations identified in the TPOgene, the NGS revealed mutations in other thyroid genes. So, Patient7 showed the novel TPO mutation: g.IVS16-2A>C and the IYDmutation: c.874C>T; p.R292C . Patient 8 carries the TPO mutations:c.920A>C, p.N307T (novel) and the c.1682C>T, p.T561M and anovel TG mutation: c.1804G>A, p.V602I. The use of new molecularbiology techniques is a valuable tool for understanding the molecularpathophysiology and for the diagnosis and treatment of this typeof thyroid defects.