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

MOLINA, MARICEL F.; BELFORTE, FIORELLA S.; ADROVER, EZEQUIELA; OLCESE, MARÍA C.; SIFFO, SOFÍA; GOMES PIO, MAURICIO; BUENO MARTÍNEZ, ELENA; GONZÁLEZ SARMIENTO, ROGELIO; TARGOVNIK, HÉCTOR M.; RIVOLTA, CARINA M.

Mar del Plata

Congreso; LXIII Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica.; 2018

Sociedad Argentina de Investigación Clínica

Iodide Organification defects (IOD) represent 10% of cases of congenital hypothyroidism (CH) being the main genes affected that of TPO and DUOX2. From eight patients with clinical and biochemical criteria suggestive with CH associated with IOD, TPO and DUOX2 genes were analyzed (Patients 1-8). In principle sequencing by the Sanger technique was carried out. In those cases in which a single mutation was identified in the TPO gene, NGS technique was used. 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 of these amplicon libraries was carried out by using the Miseq Ilumina platform. 4 novel mutations have been identied (two en TPO, one in TG and 1 in DUOX2). The heterozygous compound to the novel mutation c.2695delC, p.Q899Qfs*21 and the c.2895_2898del-GTTC, p.S965Sfs*30 was identified in the DUOX2 gene in Patient 1. Sequencing analysis of TPO gene revealed the following inactivating mutations: c.1993C>T, p.R665W and c.2395G>A, p.E799K in 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.T561M in Patient 4, c.920A>C, p.N307T (novel) and c.1727C>A, p.A576E in Patient 5; c.1186_1187insGGCC, p.R396Rfs*77 and c.1727C>A, p.A576E in Patient 6. In addition to mutations identified in the TPO gene, the NGS revealed mutations in other thyroid genes. So, Patient 7 showed the novel TPO mutation: g.IVS16-2A>C and the IYD mutation: 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 a novel TG mutation: c.1804G>A, p.V602I. The use of new molecular biology techniques is a valuable tool for understanding the molecular pathophysiology and for the diagnosis and treatment of this type of thyroid defects.