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.

First case report of rare congenital adrenal insufficiency caused by mutations in the CYP11A1 gene in the Czech Republic.

We characterized a case of congenital adrenal insufficiency caused by cholesterol side-chain cleavage enzyme (P450scc) deficiency. The patient presented after birth with cardiopulmonary instability, hyponatremia, hyperkalemia, hypoglycemia and metabolic acidosis. We confirmed primary adrenal insufficiency. There were no signs of the external genitalia virilism. The replacement therapy with glucocorticoids and mineralocorticoids led to normal laboratory results. At the age of 12 years, we confirmed hypergonadotropic hypogonadism, which revealed disorder of steroidogenesis in the adrenal glands and in the gonads. The enzymatic block was found at the beginning of steroidogenesis. The mutation was confirmed in the CYP11A1 gene. The patient is compound heterozygote for the novel CYP11A1 missense mutation c.412G>A (p.Gly138Arg) in exon 2 and frameshift mutation c.508_509delCT (p.Leu170Valfs*30) in exon 3. The CYP11A1: c.412G>A (p.Gly138Arg) was predicted as pathogenic by in silico analysis. So far, only 19 patients with CYP11A1 mutations causing P450scc deficiency have been reported worldwide. There are no related reports in the Czech Republic.