Systematic thyroid screening in myotonic dystrophy: link between thyroid volume and insulin resistance

Adrien Ben HamouEmail author View ORCID ID profile,
Stéphanie Espiard,
Christine Do Cao,
Miriam Ladsous,
Camille Loyer,
Alexandre Moerman,
Samuel Boury,
Maéva Kyheng,
Claire-Marie Dhaenens,
Vincent Tiffreau,
Pascal Pigny,
Gilles Lebuffe,
Robert Caiazzo,
Sébastien Aubert and
Marie Christine VantyghemEmail author View ORCID ID profile

Orphanet Journal of Rare Diseases201914:42

https://doi.org/10.1186/s13023-019-1019-3

Received: 12 July 2018
Accepted: 3 February 2019
Published: 13 February 2019

Abstract

Background

Myotonic dystrophy (DM1), a neuromuscular disease related to DMPK gene mutations, is associated to endocrine disorders and cancer. A routine endocrine work-up, including thyroid ultrasound (US), was conducted in 115 genetically-proven DM1 patients in a neuromuscular reference center. The aim of this study was to determine the prevalence and the causes of US thyroid abnormalities in DM1.

Results

In the whole population (age 45.1 ± 12.2 years, 61.7% female), palpable nodules or goiters were present in 29.2%. The percentage of US goiter (thyroid volume > 18 mL) and US nodules were, respectively, 38.3 and 60.9%. Sixteen of the 115 patients had a thyroidectomy, after 22 fine-needle aspiration cytology guided by thyroid imaging reporting and data system (TIRADS) classification. Six micro- (1/6 pT3) and 3 macro-papillary thyroid carcinoma (PTCs) (2/3 intermediate risk) were diagnosed (7.9% of 115). Thyroid US led to the diagnosis of 4 multifocal and 2 unifocal (including 1 macro-PTC) non-palpable PTCs. Ultrasound thyroid volume was positively correlated to body mass index (BMI) (p = 0.015) and parity (p = 0.036), and was inversely correlated to TSH (p < 0.001) and vitamin D levels (p = 0.023). The BMI, the frequencies of glucose intolerance and PTC were significantly higher in UsGoiter versus non-UsGoiter groups.

Conclusion

In this systematically screened DM1 cohort, the frequency of UsGoiter, mainly associated to BMI, was about 40%, US nodules 60%, thyroidectomies 13–14%, and PTCs 8%, two-thirds of them being micro-PTCs with good prognosis. Therefore, a systematic screening remains debatable. A targeted US screening in case of clinical abnormality or high BMI seems more appropriate.