Normalization of Spexin Levels in Patients with Obesity Submitted to Bariatric Surgery.

PURPOSE: Spexin is expressed by white fat tissue and other endocrine organs. A negative correlation between spexin and gluco-lipidic metabolism, energy homeostasis, and food intake has been reported. The objectives of this study are (1) to compare spexin levels between patients with obesity (study group) and normal-weight subjects (control group); (2) to evaluate spexin levels after bariatric surgery; and (3) to identify a correlation between spexin and weight loss/metabolic profile of patients with obesity. MATERIALS AND METHODS: We examined 53 patients with obesity (mean BMI 48.5 ± 9.4 kg/m2) who underwent bariatric surgery, compared to 55 normal-weight subjects. Serum spexin levels were assessed at baseline (study and control group) and at 3 and 6 months after surgery in patients with obesity. RESULTS: Spexin at baseline was significantly lower in the study group (p < 0.0001). At 3 and 6 months after bariatric surgery, spexin significantly increased compared to pre-surgical levels (p < 0.001) reaching control group levels (p = 0.08) at 6 months. In patients with obesity, pre-surgical spexin was similar in patients with and without comorbidities. No correlation between spexin and C-reactive protein (p = 0.8) and HOMA index (p = 0.5) was found. A significant negative correlation between age and pre-surgical spexin was observed (p = 0.03). At multivariable analysis, no correlation between Δ spexin and pre-surgery BMI, HOMA index, age, and 6-month TWL% was found. CONCLUSION: This study demonstrates that patients with obesity have significantly lower spexin levels than healthy subjects. After surgery, spexin levels of the study group become similar to those observed in the normal-weight group.

Proteomics Reveals How the Tardigrade Damage Suppressor Protein Teaches Transfected Human Cells to Survive UV-C Stress.

The genome sequencing of the tardigrade Ramazzottius varieornatus revealed a unique nucleosome-binding protein named damage suppressor (Dsup), which was discovered to be crucial for the extraordinary abilities of tardigrades in surviving extreme stresses, such as UV. Evidence in Dsup-transfected human cells suggests that Dsup mediates an overall response in DNA damage signaling, DNA repair, and cell cycle regulation, resulting in an acquired resistance to stress. Given these promising outcomes, our study attempts to provide a wider comprehension of the molecular mechanisms modulated by Dsup in human cells and to explore the Dsup-activated molecular pathways under stress. We performed a differential proteomic analysis of Dsup-transfected and control human cells under basal conditions and at 24 h recovery after exposure to UV-C. We demonstrate via enrichment and network analyses, for the first time, that even in the absence of external stimuli, and more significantly, after stress, Dsup activates mechanisms involved with the unfolded protein response, the mRNA processing and stability, cytoplasmic stress granules, the DNA damage response, and the telomere maintenance. In conclusion, our results shed new light on Dsup-mediated protective mechanisms and increases our knowledge of the molecular machineries of extraordinary protection against UV-C stress.

Pilot Study on the Impact of Polymorphisms Linked to Multi-Kinase Inhibitor Metabolism on Lenvatinib Side Effects in Patients with Advanced Thyroid Cancer.

Multi-kinase inhibitors (MKIs) represent the best therapeutic option in advanced thyroid cancer patients. The therapeutic efficacy and toxicity of MKIs are very heterogeneous and are difficult to predict before starting treatment. Moreover, due to the development of severe adverse events, it is necessary to interrupt the therapy some patients. Using a pharmacogenetic approach, we evaluated polymorphisms in genes coding for proteins involved with the absorption and elimination of the drug in 18 advanced thyroid cancer patients treated with lenvatinib, and correlated the genetic background with (1) diarrhea, nausea, vomiting and epigastric pain; (2) oral mucositis and xerostomia; (3) hypertension and proteinuria; (4) asthenia; (5) anorexia and weight loss; (6) hand foot syndrome. Analyzed variants belong to cytochrome P450 (CYP3A4 rs2242480 and rs2687116 and CYP3A5 rs776746) genes and to ATP-binding cassette transporters (ABCB1 rs1045642, rs2032582 and rs2235048 and ABCG2 rs2231142). Our results suggest that the GG genotype for rs2242480 in CYP3A4 and CC genotype in rs776746 for CYP3A5 were both associated with the presence of hypertension. Being heterozygous for SNPs in the ABCB1 gene (rs1045642 and 2235048) implicated a higher grade of weight loss. The ABCG2 rs2231142 statistically correlated with a higher extent of mucositis and xerostomia (CC genotype). Heterozygous and rare homozygous genotypes for rs2242480 in CYP3A4 and for rs776746 for CYP3A5 were found to be statistically linked to a worse outcome. Evaluating the genetic profile before starting lenvatinib treatment may help to predict the occurrence and grade of some side effects, and may contribute to improving patient management.

Type 2 deiodinase p.Thr92Ala polymorphism does not affect the severity of obesity and weight loss after bariatric surgery.

A single nucleotide polymorphism in the Type 2 deiodinase (DIO2) gene (p.Thr92Ala) was found to be associated with hypertension, type 2 diabetes mellitus (T2DM), insulin resistance, and body mass index (BMI). We retrospectively evaluated 182 patients to assess whether the DIO2 p.Thr92Ala was associated with severe obesity and response to bariatric surgery. Genomic DNA was extracted from peripheral blood leukocytes before surgery. Glycemic control parameters, cardiometabolic risk biomarkers (waist circumference, lipid assessment and blood pressure) and hormonal parameters were assessed at baseline and after surgery. Based on genotype evaluation, 78/182 (42.9%) patients were homozygous wild-type (Thr/Thr), 83/182 (45.6%) heterozygous (Thr/Ala), and 21/182 (11.5%) rare homozygous (Ala/Ala). Age at the time of the first evaluation in our Unit was significantly lower in patients with DIO2 p.Thr92Ala. No significant association was observed between DIO2 p.Thr92Ala and BMI, excess weight, waist circumference, Homa Index. The prevalence of comorbidities was not associated with allele distribution except for hypertension that was more frequent in wild-type patients (p = 0.03). After bariatric surgery, excess weight loss (EWL) % and remission from comorbidities occurred without differences according to genotypes. DIO2 p.Thr92Ala does not affect the severity of obesity and its complications, but it seems to determine an earlier onset of morbid obesity. The presence of polymorphism seems not to impact on the response to bariatric surgery, both in terms of weight loss and remission of comorbidities.

PAPPA Expression in Indeterminate Thyroid Nodules as Screening Test to Select Patients for Molecular Testing.

Pregnancy-associated plasma protein A (PAPPA) acts as an oncogene, and its expression is increased in multiple malignancies, including thyroid cancer. Molecular tests represent a useful tool in the management of indeterminate thyroid nodules; however, they are not conducted in all centers, and they contribute to increase the per-patient cost of nodule evaluation. In this study, we examined whether PAPPA expression could represent a promising new screening test in the management of indeterminate thyroid nodules. Toward this aim, PAPPA expression was evaluated in 107 fine needle aspiration cytologies (FNAC) belonging to Bethesda III-IV categories that had been sent to molecular biology to discriminate the nature of the nodules. We found that the PAPPA expression increased and showed an elevated sensitivity (97.14%) and negative predictive value (98%) in indeterminate cytological samples positive for mutations. The enhanced expression was not linked to a specific oncogene. Our findings demonstrated that assessing the PAPPA expression in indeterminate thyroid cytologies could represent a useful screening tool to select all patients that effectively need to be sent to molecular testing, thereby, leading to a potential cost reduction in the management of patients.

BDNF and Pro-BDNF in Amyotrophic Lateral Sclerosis: A New Perspective for Biomarkers of Neurodegeneration.

Amyotrophic Lateral Sclerosis (ALS) is characterized by the progressive degeneration of upper or lower motor neurons, leading to muscle wasting and paralysis, resulting in respiratory failure and death. The precise ALS aetiology is poorly understood, mainly due to clinical and genetic heterogeneity. Thus, the identification of reliable biomarkers of disease could be helpful in clinical practice. In this study, we investigated whether the levels of brain-derived neurotrophic factor (BDNF) and its precursor Pro-BDNF in serum and cerebrospinal fluid (CSF) may reflect the pathological changes related to ALS. We found higher BDNF and lower Pro-BDNF levels in ALS sera compared to healthy controls. BDNF/Pro-BDNF ratio turned out to be accurate in distinguishing ALS patients from controls. Then, the correlations of these markers with several ALS clinical variables were evaluated. This analysis revealed three statistically significant associations: (1) Patients carrying the C9orf72 expansion significantly differed from non-carrier patients and showed serum BDNF levels comparable to control subjects; (2) BDNF levels in CSF were significantly higher in ALS patients with faster disease progression; (3) lower serum levels of Pro-BDNF were associated with a shorter survival. Therefore, we suggest that BDNF and Pro-BDNF, alone or in combination, might be used as ALS prognostic biomarkers.

Alteration of Serum Proteome in Levo-Thyroxine-Euthyroid Thyroidectomized Patients.

The monotherapy with levo-thyroxine (LT4) is the treatment of choice for patients with hypothyroidism after thyroidectomy. However, many athyreotic LT4-treated patients with thyroid hormones in the physiological range experience hypothyroid-like symptoms, showing post-operative, statistically significant lower FT3 levels with respect to that before total thyroidectomy. Since we hypothesized that the lower plasmatic FT3 levels observed in this subgroup could be associated with tissue hypothyroidism, here we compared, by a preliminary proteomic analysis, eight sera of patients with reduced post-surgical FT3 to eight sera from patients with FT3 levels similar to pre-surgery levels, and six healthy controls. Proteomic analysis highlights a different serum protein profile among the considered conditions. By enrichment analysis, differential proteins are involved in coagulation processes (PLMN-1.61, -1.98 in reduced vs. stable FT3, p < 0.02; A1AT fragmentation), complement system activation (CFAH + 1.83, CFAB + 1.5, C1Qb + 1.6, C1S + 7.79 in reduced vs. stable FT3, p < 0.01) and in lipoprotein particles remodeling (APOAI fragmentation; APOAIV + 2.13, p < 0.003), potentially leading to a pro-inflammatory response. This study suggests that LT4 replacement therapy might restore biochemical euthyroid conditions in thyroidectomized patients, but in some cases without re-establishing body tissue euthyroidism. Since our results, this condition is reflected by the serum protein profile.

The Tardigrade Damage Suppressor Protein Modulates Transcription Factor and DNA Repair Genes in Human Cells Treated with Hydroxyl Radicals and UV-C.

The Ramazzottius varieornatus tardigrade is an extremotolerant terrestrial invertebrate with a length of 0.1-1.0 mm. These small animals show an extraordinary tolerance to extreme conditions such as high pressure, irradiation, chemicals and dehydration. These abilities are linked to a recently discovered damage suppressor protein (Dsup). Dsup is a nucleosome-binding protein that avoids DNA damage after X-ray and oxidative stress exposure without impairing cell life in Dsup-transfected animal and plant cells. The exact "protective" role of this protein is still under study. In human cells, we confirmed that Dsup confers resistance to UV-C and H2O2 exposure compared to untransfected cells. A different transcription factor activation was also observed. In addition, a different expression of endogenous genes involved in apoptosis, cell survival and DNA repair was found in Dsup+ cells after H2O2 and UV-C. In UV-C exposed cells, Dsup efficiently upregulates DNA damage repair genes, while H2O2 treatment only marginally involves the activation of pathways responsible for DNA repair in Dsup+ cells. These data are in agreement with the idea of a direct protective effect of the protein on DNA after oxidative stress. In conclusion, our data may help to outline the different mechanisms by which the Dsup protein works in response to different insults.

Autosomal dominant familial neurohypophyseal diabetes insipidus caused by a novel missense mutation in AVP gene in a large Italian kindred.

PURPOSE: Familial neurohypophysial diabetes insipidus (FNDI), commonly caused by autosomal dominant arginine vasopressin (AVP) mutations, is a rare condition in which vasopressin fails in regulating body's level of water with final polyuria and polydipsia. Genetic testing in familial cases of FNDI should be carry out to ensure adequate treatments and avoid disease manifestations especially in infants. METHODS: In this study, we investigated three-generations of a large Italian family with clinical diagnosis of familial central diabetes insipidus for the presence of potential pathogenic mutations in the AVP gene. RESULTS: We identified a heterozygous missense mutation (c.154 T > A; p.C52S) in AVP gene in all affected members studied of a large Italian family. In silico tools were used to investigate the pathogenic role of the mutation and three-dimensional protein structure predicted that the p.C52S impairs disulfide bridges formation resulting in misfolding of the protein. CONCLUSIONS: This is the first study that identified a novel missense p.C52S mutation as causative of central diabetes insipidus in a large Italian pedigree.

The impact of CPT1B rs470117, LEPR rs1137101 and BDNF rs6265 polymorphisms on the risk of developing obesity in an Italian population.

OBJECTIVE: This study aimed to analyze 11 single nucleotide polymorphisms (SNPs) belonging to 9 genes involved in metabolic pathways (BDNF rs6265; PNPLA3 rs2294918 and rs2076212; CIDEA rs11545881; NTRK2 rs2289658; ALOX12 rs1126667; ALOX12B rs2304908; LEPR rs1137101; CPT1B rs470117 and rs8142477; rs2305507 CPT1A) in obese patients and controls. METHODS: Polymorphisms were analyzed in 300 severe obese patients undergoing bariatric surgery (body mass index >30 kg/m2) and 404 control subjects in order to evaluate their association with obesity and clinical variables. RESULTS: Our findings showed significant differences for the allelic distributions of CPT1B rs470117 and LEPR rs11371010 in obese subjects compared to controls. The BDNF rs6265 correlates with obesity only when associated with the other two SNPs. In particular, for CPT1B rs470117 and LEPR rs1137101, the rare allele was associated with a reduced risk of developing the obese phenotype, whereas the simultaneous presence of the common C allele for rs470117 and A allele for rs1137101 was more frequent in obese patients (p = 0.002, OR = 1.417). A significant association between CPT1B rs470117 and steatosis was found. Moreover, we observed that by associating the rare allele T of the BDNF rs6265 with the most common alleles of the SNPs CPT1B rs470117 and LEPR rs1137101, the combination of T-C-A alleles was associated with a higher risk of developing an obese phenotype (p = 0.001, OR = 1.6679). CONCLUSIONS: Our results suggest that SNPs CPT1B rs470117 and LEPR rs1137101 taken individually and in association with BDNF rs6265 may be involved in an increased risk of developing obese phenotype in an Italian cohort.

miRNA Targets: From Prediction Tools to Experimental Validation.

MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression in both animals and plants. By pairing to microRNA responsive elements (mREs) on target mRNAs, miRNAs play gene-regulatory roles, producing remarkable changes in several physiological and pathological processes. Thus, the identification of miRNA-mRNA target interactions is fundamental for discovering the regulatory network governed by miRNAs. The best way to achieve this goal is usually by computational prediction followed by experimental validation of these miRNA-mRNA interactions. This review summarizes the key strategies for miRNA target identification. Several tools for computational analysis exist, each with different approaches to predict miRNA targets, and their number is constantly increasing. The major algorithms available for this aim, including Machine Learning methods, are discussed, to provide practical tips for familiarizing with their assumptions and understanding how to interpret the results. Then, all the experimental procedures for verifying the authenticity of the identified miRNA-mRNA target pairs are described, including High-Throughput technologies, in order to find the best approach for miRNA validation. For each strategy, strengths and weaknesses are discussed, to enable users to evaluate and select the right approach for their interests.

EIF1AX c.338-2A>T splice site mutation in a patient with trabecular adenoma and cytological indeterminate lesion.

The EIF1AX gene mutations have been recently associated with papillary thyroid carcinoma and anaplastic thyroid cancer. According with these reports, the gene as been considered as a drive gene for thyroid cancer development. However, the occurrence of these alterations in benign thyroid lesions is not known and is still under investigation. Some authors have already reported the presence of EIF1AX variants in follicular adenomas and hyperplastic nodules. Here, we describe for the first time a case of a man with the EIF1AX c.338-2A>T splice site mutation in an indeterminate FNA lesion with trabecular adenoma at final histology in the absence of other pathogenetic mutations, demonstrating that further studies are required to better understand EIF1AX role in the tumorigenesis of thyroid carcinoma.

EIF1AX c.338-2A>T splice site mutation in a patient with trabecular adenoma and cytological indeterminate lesion

SUMMARY The EIF1AX gene mutations have been recently associated with papillary thyroid carcinoma and anaplastic thyroid cancer. According with these reports, the gene as been considered as a drive gene for thyroid cancer development. However, the occurrence of these alterations in benign thyroid lesions is not known and is still under investigation. Some authors have already reported the presence of EIF1AX variants in follicular adenomas and hyperplastic nodules. Here, we describe for the first time a case of a man with the EIF1AX c.338-2A>T splice site mutation in an indeterminate FNA lesion with trabecular adenoma at final histology in the absence of other pathogenetic mutations, demonstrating that further studies are required to better understand EIF1AX role in the tumorigenesis of thyroid carcinoma.

Vemurafenib may overcome TNF-related apoptosis-inducing ligand (TRAIL) resistance in anaplastic thyroid cancer cells.

PURPOSE: Anaplastic thyroid cancer (ATC) is rare but with poor prognosis. TRAIL can selectively induce apoptosis in cancer cells; however, resistance is quite common. Aim of our study was to evaluate TRAIL-induced apoptosis in ATC-derived cell lines, in vitro and in vivo, and the effect of combination with tyrosine kinase inhibitors (TKIs) selective for BRAF (vemurafenib) or Akt (MK-2206). METHODS: Four ATC-derived cell lines were used: C643, CAL62, HTh7, with activating mutation of RAS and copy gain of PI3K (HTh7) and, 8505C with activating mutation of BRAF. Cells were treated with TRAIL alone or in combination with vemurafenib or MK-2206. The pro-apoptotic effect of TRAIL alone or combined with TKIs was, also, evaluated in two mouse xenograft models (HTh7 and 8505C). RESULTS: C643, CAL62, and HTh7 cells were sensitive to TRAIL-induced apoptosis, whereas 8505C cells were resistant. Both in vitro and in vivo vemurafenib was able to increase the TRAIL-induced apoptosis in 8505C cells causing a slower tumor growth in 8505C xenograft compared to placebo, while MK-2206 did not have any additive effect on TRAIL treatment in HTh7 model. CONCLUSIONS: TRAIL is a promising therapeutic agent in ATC and in case of resistance vemurafenib may be a valid complementary therapy.

RARE POMC MUTATION IN A PATIENT WITH MYOTONIC DYSTROPHY TYPE 1 AND ADRENOCORTICOTROPIN HYPERRESPONSE TO CORTICOTROPIN-RELEASING HORMONE.

OBJECTIVE: Myotonic dystrophy (DM) is a monogenic disorder. It is caused by expansion of a cytosine-thymineguanine triplet in the DMPK gene which encodes for myotonic dystrophy protein kinase (DMPK). METHODS: A 24-year-old man with DM and the DMPK mutation presented with elevated adrenocorticotropic hormone (ACTH) levels twice (152 and 185 pg/mL; normal value is 10 to 52 pg/mL) with normal cortisol levels (134.6 and 113.0 ng/mL, or 371.3 and 311.7 nmol/L; normal values are 67 to 226 ng/mL or 184.8 to 623.5 nmol/L). ACTH, corticotropin-releasing hormone (CRH) and insulin tolerance test (ITT) demonstrated normal cortisol response to ACTH and partial response to CRH and ITT tests, and ACTH hyperresponse to CRH and ITT. We suspected ACTH and/or ACTH receptor (ACTHR) mutations and evaluated the genetic profile for pro-opiomelanocortin (POMC), melanocortin 2 receptor (MC2R) and follicle-stimulating hormone receptor (FSHR) genes. RESULTS: No mutations were found in either the MC2R or FSHR genes. The patient was heterozygous for the c.614A>G mutation corresponding to a p.53D>G substitution with a glycine instead of an aspartate in position 53 in POMC gene. This mutation was outside the sequence for ACTH (which spans amino acids 138 to 176) but was included in the part originating the N-terminal peptide of pro-opiomelanocortin (also called pro-γ-melanocyte stimulating hormone) which spans amino acids 27 to 102 and is involved in the regulation of adrenal steroidogenesis. CONCLUSION: The pathologic expansion of the cytosine-thymine-guanine triplet repeat in the 3' noncoding region of DMPK could explain the hyperresponse of ACTH typical of DM. The mutation of pro-γ-melanocyte-stimulating hormone could be associated with the abnormal response of cortisol, compatible with a partial adrenal insufficiency. Other studies are necessary to demonstrate this hypothesis.

MicroRNAs as Biomarkers in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is an incurable and fatal disorder characterized by the progressive loss of motor neurons in the cerebral cortex, brain stem, and spinal cord. Sporadic ALS form accounts for the majority of patients, but in 1⁻13.5% of cases the disease is inherited. The diagnosis of ALS is mainly based on clinical assessment and electrophysiological examinations with a history of symptom progression and is then made with a significant delay from symptom onset. Thus, the identification of biomarkers specific for ALS could be of a fundamental importance in the clinical practice. An ideal biomarker should display high specificity and sensitivity for discriminating ALS from control subjects and from ALS-mimics and other neurological diseases, and should then monitor disease progression within individual patients. microRNAs (miRNAs) are considered promising biomarkers for neurodegenerative diseases, since they are remarkably stable in human body fluids and can reflect physiological and pathological processes relevant for ALS. Here, we review the state of the art of miRNA biomarker identification for ALS in cerebrospinal fluid (CSF), blood and muscle tissue; we discuss advantages and disadvantages of different approaches, and underline the limits but also the great potential of this research for future practical applications.

Diagnostic Value of Circulating microRNA-95 and -190 in the Differential Diagnosis of Thyroid Nodules: A Validation Study in 1000 Consecutive Patients.

BACKGROUND: It has recently been demonstrated that the combination of miRNA-190 and -95 (expressed as probability of malignant risk: pmiRNA) in the serum of Caucasian patients with thyroid nodular disease allows the identification of nodules at high risk of malignancy with great accuracy. The present study aimed to validate these results in a larger cohort of patients. MATERIALS AND METHODS: This study prospectively analyzed 1000 patients. Cytological diagnosis was available in 982/1000 (98.2%) and histological diagnosis in 445/1000 (44.5%). The expression levels of circulating miRNA-190 and -95 were determined by real time polymerase chain reaction with the 2-ΔΔct method. The diagnostic performance (sensitivity, specificity, and accuracy) of fine-needle aspiration cytology (FNAC), pmiRNA, and a combination of the two methods was correlated with the cytological and histological diagnoses. RESULTS: The combination of pmiRNA and FNAC significantly increased the sensitivity (96.3%) with respect to each method alone (88.9% for FNAC and 89.6% for pmiRNA) by reducing the rate of false-negative results from 18 for FNAC and 17 for pmiRNA to only five. In patients in whom FNAC was not performed (n = 14) or in those with inadequate (n = 18) or indeterminate (n = 72) lesions submitted to surgery, pmiRNA correctly identified 90.8% of patients with benign disease and 74.3% of patients with cancer. CONCLUSIONS: These results confirm that a combination of serum expression levels of miRNA-95 and -190 is an accurate and noninvasive tool for the differential diagnosis of thyroid nodules in the Italian population.

Molecular Signature of Indeterminate Thyroid Lesions: Current Methods to Improve Fine Needle Aspiration Cytology (FNAC) Diagnosis.

Fine needle aspiration cytology (FNAC) represents the gold standard for determining the nature of thyroid nodules. It is a reliable method with good sensitivity and specificity. However, indeterminate lesions remain a diagnostic challenge and researchers have contributed molecular markers to search for in cytological material to refine FNAC diagnosis and avoid unnecessary surgeries. Nowadays, several "home-made" methods as well as commercial tests are available to investigate the molecular signature of an aspirate. Moreover, other markers (i.e., microRNA, and circulating tumor cells) have been proposed to discriminate benign from malignant thyroid lesions. Here, we review the literature and provide data from our laboratory on mutational analysis of FNAC material and circulating microRNA expression obtained in the last 6 years.

DIO2 Thr92Ala Reduces Deiodinase-2 Activity and Serum-T3 Levels in Thyroid-Deficient Patients.

Context: A substantial proportion of athyreotic levothyroxine (LT4)-treated patients experience hypothyroid-like symptoms. During LT4 replacement, levels of the active hormone triiodothyronine (T3) strictly depend on type 2-deiodinase (D2)-mediated activation of LT4. The Thr92Ala polymorphism and the 258 G/A in the DIO2 gene have been associated with various clinical conditions. Objectives: To investigate the effects of DIO2 polymorphisms in thyroid hormone homeostasis. Design: We compared the presurgical hormonal status of thyroidectomized LT4-treated patients who had a similar thyroid-stimulating hormone (TSH) level with their postsurgery status and analyzed their DIO2 genotype in a subgroup of 102/140 (72.8%) of patients. We measured the enzymatic properties of Thr92Ala in living cells and in relevant generated mouse models. Subjects and methods: A total of 140 thyroidectomized subjects were included. Serum free T3 (FT3), free thyroxine, and TSH levels were directly measured. Immunohistochemistry and immunoblotting were performed for D2 protein. Results: The DIO2 genotyping revealed an association between low FT3 values and Thr92Ala. Specifically, the mean postsurgery FT3 levels were significantly lower in patients carrying the mutated allele(s) than in wild-type patients, in whom FT3 postsurgical levels were similar to presurgery levels. The -258 G/A variation was not associated with hormonal alteration. We found that endogenous wild-type D2 and Thr92Ala share the same subcellular localization but differ in protein stability. Importantly, Thr92Ala reduced D2-mediated thyroxine to T3 conversion. Conclusions: Thyroidectomized patients carrying Thr92Ala are at increased risk of reduced intracellular and serum T3 concentrations that are not adequately compensated for by LT4, thus providing evidence in favor of customized treatment of hypothyroidism in athyreotic patients.