Clinical, biochemical, and molecular findings in Argentinean patients with goitrous congenital hypothyroidism

Long-Term Outcome of Patients with TPO Mutations

INTRODUCTION

Thyroid peroxidase (TPO) deficiency is the most common enzymatic defect causing congenital hypothyroidism (CH). We aimed to characterize the long-term outcome of patients with TPO deficiency.

METHODS

Clinical and genetic data were collected retrospectively.

RESULTS

Thirty-three patients with primary CH caused by TPO deficiency were enrolled. The follow-up period was up to 43 years. Over time, 20 patients (61%) developed MNG. Eight patients (24%) underwent thyroidectomy: one of them had minimal invasive follicular thyroid carcinoma. No association was found between elevated lifetime TSH levels and the development of goiter over the years.

CONCLUSIONS

This cohort represents the largest long-term follow up of patients with TPO deficiency. Our results indicate that elevated TSH alone cannot explain the high rate of goiter occurrence in patients with TPO deficiency, suggesting additional factors in goiter development. The high rate of MNG development and the risk for thyroid carcinoma indicate a need for long-term follow up with annual ultrasound scans.

Large thyroid cyst in a patient with congenital hypothyroidism

Thyroid hormone biosynthetic defects are rare causes of congenital hypothyroidism. Although, initial presentations are usually diffuse goiter and hypothyroidism, subsequently they may develop thyroid nodules and or thyroid cancer. We describe a case of hypothyroidism due to dyshormonogenesis whose one of the previously solid nodules degenerates into a large cyst. A 22-year-old male was referred to our clinic for evaluation of enlarging thyroid nodule. Hypothyroidism was diagnosed in infancy, however due to poor compliance to treatment TSH values were elevated most of the times. When he was fifteen the first nodule was detected which was a solid cold nodule. Fine needle aspiration was in favor of benign follicular nodule. Seven years later we found a large multi nodular thyroid with a predominant large cyst corresponding to the previously detected solid nodule. 21cc straw colored fluid was aspirated. Cytology was reported as benign cystic nodule. The patient underwent thyroidectomy and pathology confirmed a benign thyroid cyst. Although underreported thyroid dyshormonogenesis may progress to cystic degeneration. Taking into account the risk of malignancy and eventually cyst formation, we recommend more frequent evaluation in the face of nodule formation in these patients.

Genotypes and phenotypes of congenital goitre and hypothyroidism caused by mutations in dual oxidase 2 genes

OBJECTIVE

The aim of this study was to screen for DUOX2, TPO and TG mutations in Chinese patients with congenital hypothyroidism (CH) and goitre and to define the relationships between DUOX2 genotypes and clinical phenotypes.

METHODS

Blood samples were collected from 67 patients with CH and goitre in Shandong Province, China. Genomic DNA was extracted from peripheral blood leucocytes. PCR and direct sequencing were used to analyse all exons of DUOX2, TPO and TG. Detailed medical records were then collected, and the relationship between DUOX2 genotype and the clinical phenotype of CH and goitre caused by DUOX2 mutations was investigated.

RESULTS

Analysis of DUOX2 revealed nine mutations, including one novel nonsense mutation (p.W734X), six novel missense mutations (p.N100D, p.S660L, p.A1131S, p.W1181G, p.A1206T and p.R1267W) and two recurrent mutations (p.R701X and p.R1110Q) in 10 patients from 10 unrelated families. Monoallelic and compound heterozygous mutations in DUOX2 were associated with permanent or transient CH. No mutation was found after screening all exons of TPO and TG.

CONCLUSION

Our study identified DUOX2 mutations in 14·9% of Chinese patients investigated with CH and goitre. Because the relationships between DUOX2 genotypes and clinical phenotypes are extremely complex, however, further studies are needed to identify more mutations in known genes which are involved in CH and goitre.