First 2 cases with thiamine-responsive megaloblastic anemia in the Czech Republic, a rare form of monogenic diabetes mellitus: a novel mutation in the thiamine transporter SLC19A2 gene-intron 1 mutation c.204+2T>G.

Thiamine-responsive megaloblastic anemia (TRMA) is a rare autosomal recessive disorder caused by mutations in the SLC19A2 gene. To date at least 43 mutations have been reported for the gene encoding a plasma membrane thiamine transporter protein (THTR-1). TRMA has been reported in less than 80 cases worldwide. Here, we illustrate 2 female patients with TRMA first diagnosed in the Czech Republic and in central Europe being confirmed by sequencing of the THTR-1 gene SLC19A2. Both subjects are compound heterozygotes with 3 different mutations in the SLC19A2 gene. In case 2, the SLC19A2 intron 1 mutation c.204+2T>G has never been reported before. TRMA subjects are at risk of diabetic ketoacidosis during intercurrent disease and arrythmias. Thiamine supplementation has prevented hematological disorders over a few years in both pediatric subjects, and improved glycaemic control of diabetes mellitus. Patient 1 was suffering from hearing loss and rod-cone dystrophy at the time of diagnosis, however, she was unresponsive to thiamine substitution. Our patient 2 developed the hearing loss despite the early thiamine substitution, however no visual disorder had developed. The novel mutation described here extends the list of SLC19A2 mutations causing TRMA.

Autoimmune disease, familial clustering and thyroid carcinoma coexistent with autoimmune thyroiditis in children and adolescence: A cross-sectional study from the Czech Republic.

BACKGROUND: The prevalence of autoimmune thyroiditis (AIT), as the most common autoimmune disease (AD) and papillary thyroid cancer (PTC) is steadily rising in children. The aim of this study was to determine the coexistence of other AD and thyroid carcinoma (TC) in AIT. METHODS: The cross-sectional study conducted at a tertiary center comprised AIT children (< 19 years). Data on age/sex, thyroid function and ultrasound, autoantibodies, associated AD, familial occurence of AD and the occurence of TC for each child were collected. RESULTS: In total, 231 eligible patients (77% females) were included. The most common onset (66%) was during adolescence. At onset, hypothyroidism was detected in 59.3%; hashitoxicosis in 1.3%. The positivity of both autoantibodies was present in 60.6%, the negativity was in 3,5%. We confirmed a high frequency (44.6%) of AD with AIT predominance in parents and/or grandparents of patients and in siblings (7.4%). 15.2% had at least 1 comorbid AD, of which type 1 diabetes mellitus was the most common (8.5%). Over a period of 7 years TC was diagnosed in 16 patients (mean age 13.5 years) with predominance of PTC in 15 (94%) patients. AIT had concurrently 69% patients. 56% of patients had metastases (89% in AIT subjects). An invasive PTC was present in 44% (86% in AIT subjects). CONCLUSIONS: The prevalence rate of AD in AIT and first-degree relatives is high, and several new associations have been reported. Providers should be aware of comorbidities and TC in AIT as this would help in early diagnoses and timely interventions.