Clinical and laboratory features of children and adolescents with congenital hypothyroidism due to dyshormonogenesis in southern Brazil.
OBJECTIVE
To characterize the phenotype of patients with congenital hypothyroidism (CH) due to dyshormonogenesis, and to hypothesize on the degree of genetic defect.


METHODS
Patients with dyshormonogenesis were subdivided into G1 (radioactive iodine uptake, RAIU > 15%; n = 62) and G2 (RAIU < 15%; n = 32). Thyroglobulin (TG) was measured in all patients; perchlorate discharge test (PDT) was performed in G1; and saliva-to-plasma radioiodine ratio (I- S/P) in G2.


RESULTS
Levels of TSH, TT4, and FT4 before treatment and upon diagnosis confirmation were significantly different in both groups, but not between groups. In G1, 27 patients developed goiter; 17 had positive PDT (14%-71% discharge), 11 had TG < 2.5 ng/dL (one with high TSH), and one developed thyroid carcinoma. In G2, four patients developed goiter, and three had low I- S/P.


CONCLUSIONS
These data suggest an iodide organification defect in 17 cases; an iodide transport defect (NIS defect) in three, probable TSH resistance in 10, and a TG synthesis defect in two cases.
Unidade de Endocrinologia Pediátrica, Departamento de Pediatria, Hospital de Clínicas, Universidade Federal do Paraná (HC-UFPR), Curitiba, PR, Brazil.
Juliana Cristina Romero Rojas
JC
Ramos
Luiz de
Ld
Lacerda Filho
Adriane de André Cardoso
Ade A
DeMartini
Rodrigo Bruel da
RB
Silveira
Rosana Marques
RM
Pereira
Romolo
R
Sandrini Neto
Suzana Nesi
SN
França
D000293:Adolescent; D001938:Brazil; D002648:Child; D003409:Congenital Hypothyroidism / Q000175:diagnosis / Q000235:genetics*; D006042:Goiter / Q000175:diagnosis / Q000235:genetics*; D006801:Humans; D007454:Iodides / Q000378:metabolism*; D007455:Iodine / Q000097:blood*; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D010472:Perchlorates; D010641:Phenotype; D012463:Saliva / Q000737:chemistry; D013954:Thyroglobulin / Q000097:blood*; D013972:Thyrotropin / Q000097:blood*
D007454:Iodides; D007457:Iodine Radioisotopes; D010472:Perchlorates; D013972:Thyrotropin; D013954:Thyroglobulin; D007455:Iodine