Alessandro Mussa

The KCNQ1OT1 Imprinting Control Region and non-coding RNA: new properties derived from the study of Beckwith-Wiedemann syndrome and Silver-Russell syndrome cases

A cluster of imprinted genes at chromosome 11p15.5 is associated with the growth disorders, Silver–Russell syndrome (SRS) and Beckwith–Wiedemann syndrome (BWS). The cluster is divided into two domains with independent imprinting control regions (ICRs). We describe two maternal 11p15.5 microduplications with contrasting phenotypes. The first is an inverted and in cis duplication of the entire 11p15.5 cluster associated with the maintenance of genomic imprinting and with the SRS phenotype. The second is a 160 kb duplication also inverted and in cis, but resulting in the imprinting alteration of the centromeric domain. It includes the centromeric ICR (ICR2) and the most 5′ 20 kb of the non-coding KCNQ1OT1 gene. Its maternal transmission is associated with ICR2 hypomethylation and the BWS phenotype. By excluding epigenetic mosaicism, cell clones analysis indicated that the two closely located ICR2 sequences resulting from the 160 kb duplication carried discordant DNA methylation on the maternal chromosome and supported the hypothesis that the ICR2 sequence is not sufficient for establishing imprinted methylation and some other property, possibly orientation-dependent, is needed. Furthermore, the 1.2 Mb duplication demonstrated that all features are present for correct imprinting at ICR2 when this is duplicated and inverted within the entire cluster. In the individuals maternally inheriting the 160 kb duplication, ICR2 hypomethylation led to the expression of a truncated KCNQ1OT1 transcript and to down-regulation of CDKN1C. We demonstrated by chromatin RNA immunopurification that the KCNQ1OT1 RNA interacts with chromatin through its most 5′ 20 kb sequence, providing a mechanism likely mediating the silencing activity of this long non-coding RNA.

Thyroid nodules and cancer in children and adolescents affected by autoimmune thyroiditis

OBJECTIVE To investigate the association between juvenile autoimmune thyroiditis (JAT) and thyroid cancer in pediatric patients. DESIGN We conducted a retrospective study among children and adolescents affected by JAT. SETTINGS Data from 6 Italian pediatric endocrinology centers were collected. PARTICIPANTS Three hundred sixty-five children and adolescents affected by JAT diagnosed at 3.6 to 17.0 years of age. INTERVENTIONS All patients underwent clinical examination and thyroid function test every 6 to 12 months and thyroid echography every 12 to 24 months. Fine-needle aspiration biopsy was performed in 39 patients with nodule diameter of 1 cm or larger, as well as in 4 patients with nodule diameter of less than 1 cm and echographic findings suspicious for neoplasm. Twenty-three patients underwent surgery. MAIN OUTCOME MEASURES Thyroid function, echographic pattern, nodule diameter, the presence of lymphadenopathy, and cytologic and histologic diagnoses were considered. RESULTS Thyroid nodules were found in 115 patients; findings in 11 of these were consistent with papillary carcinoma, with 5 exhibiting lymph node metastasis. The prevalence of male sex among patients with cancer was greater than that among patients with JAT (odds ratio [OR], 2.95; 95% confidence interval [CI], 1.44-6.20). The growth of nodules during levothyroxine sodium therapy (OR, 15.60; 95% CI, 1.87-181.90) and the finding of lymphadenopathy (OR, 5.44; 95% CI, 1.05-30.50) were statistically significantly associated with the presence of cancer, while uninodularity and hypoechogenicity were not. CONCLUSIONS The observed prevalences of thyroid nodules and thyroid cancer in our JAT case series were 31.5% and 3.0%, respectively. Papillary carcinoma was the only histotype detected. The finding of lymphadenopathy, a lack of response to levothyroxine therapy, and nodule hypoechogenicity suggested malignancy. Fine-needle aspiration biopsy was reliable in selecting patients for referral to surgery.

The natural history of the normal/mild elevated TSH serum levels in children and adolescents with Hashimoto’s thyroiditis and isolated hyperthyrotropinaemia: a 3‐year follow‐up

Objective  The natural history of Hashimoto’s thyroiditis (HT) and isolated hyperthyrotropinaemia (IH) is not well defined. We therefore studied the natural course of patients with HT and IH and looked for possible prognostic factors.

Galectin-3: Presurgical marker of thyroid follicular epithelial cell-derived carcinomas

Preoperative follicular lesion characterisation represents an unsolved diagnostic problem in thyroid nodular disease. Although fine-needle aspiration biopsy is the most reliable preoperative diagnostic procedure, it shows inherent limitations in differentiating adenoma from follicular carcinoma and, sometimes, follicular variants of papillary carcinoma. Galectin-3 cytoplasmic neoexpression has been proposed as a peculiar feature of thyroid malignant cells, easily detectable in cytological and histological samples. The aim of this study was to re-evaluate the galectin-3 expression in a large sample of thyroid lesions using an immunohistocytochemical biotin-free detection system and a specific anti-human-galectin-3 monoclonal antibody in order to avoid the interference of technical factors, a cause of conflicting results recently reported by some authors. We analysed galectin-3 expression of 39 follicular carcinomas, 26 papillary carcinomas, and 105 adenomas in both cell-block samples and their histological counterparts. All cell-block and histological papillary carcinoma samples showed high levels of galectin-3 immunoreactivity. Thirty-four follicular carcinomas were positive, whereas 5 were negative in cell-blocks but positive in their histological counterparts. Twelve out of 105 adenomas expressed galectin-3 in cell-blocks and histological samples. The diagnostic accuracy of preoperative galectin-3 evaluation in adenomas vs follicular carcinomas was 90.0%. Galectin-3 expression was also investigated in 22 minimally-invasive follicular carcinomas. All of them showed galectin-3 immunoreactivity in both cytological and histo-logical specimens with the exception of two cases, where galectin-3 positivity was observed only in the surgical material. The routine correct use of galectin-3, by increasing the diagnostic accuracy of conventional cytology, improves the management of thyroid nodules and can lead to a sensitive reduction of useless thyroid surgeries.

Sperm count of young men surgically treated for cryptorchidism in the first and second year of life: fertility is better in children treated at a younger age.

INTRODUCTION Recent data has indicated the usefulness of performing orchiopexy in the first years of life. In this study, we evaluated testicular function in young men operated on for cryptorchidism in the first year of life. To our knowledge, this is the first report on the effects of such an early treatment. MATERIALS AND METHODS Testicular function was assessed in a group of young men operated for cryptorchidism during the first year of life (Group A, n=13) and during the second year of life (Group B, n=16). RESULTS Total sperm counts were clearly higher in Group A (52.3+/-14.3 million/ml vs. 30.4+/-23.5 million/ml, p=0.005) as was sperm motility (36.2+/-8.7 vs. 23.1+/-15.7%, p=0.009). A clear inverse relationship was found between age at orchiopexy and total sperm count (r=-0.394, p=0.034) and sperm motility (r=-0.382, p=0.041). The relationship between volume of testes, position at surgery, uni/bilaterality of cryptorchidism, evidence of Ad spermatogonia at biopsy performed during surgery and treatment with LHRH and hCG performed before surgery and fertility was not significant. The latter findings may be partially explained by the low number of patients participating in the study and need further investigation. CONCLUSIONS We obtained, for the first time, results showing the benefit of treating cryptorchidism during the first year of life rather than in the second year or even later.

Comparative Evaluation of Therapy with L -Thyroxine versus No Treatment in Children with Idiopathic and Mild Subclinical Hypothyroidism

Background: The question of whether children with subclinical hypothyroidism (SH) should be treated or not is controversial due to the lack of studies on outcomes of SH children treated with L-thyroxine (L-T4) versus those receiving no therapy. Objectives: (a) To evaluate thyroid tests under L-T4 and after therapy withdrawal in 69 SH children (group A) and (b) to compare our results with those recorded in 92 untreated children (group B). Design: Group A children were treated for 24 months and TSH and FT4 levels 3 months after therapy withdrawal were compared with those measured in group B at the end of follow-up in order to investigate treatment effects. Results: The prevalence of children who had normalized TSH at the end of follow-up was higher in group A, but the prevalence of those who had normalized or maintained unchanged TSH was similar in the two groups, as was the prevalence of children who exhibited a TSH increase >10 mU/l. In group A, TSH values at 27 months were associated with baseline values. Conclusions: (a) Two-year treatment in SH children is unable to modify posttherapy outcome of hyperthyrotropinemia; (b) therapy is unable to prevent the risk of further TSH increase after treatment withdrawal, and (c) posttherapy TSH outcome is conditioned by baseline TSH.

(Epi)genotype–phenotype correlations in Beckwith–Wiedemann syndrome

Beckwith–Wiedemann syndrome (BWS) is characterized by cancer predisposition, overgrowth and highly variable association of macroglossia, abdominal wall defects, nephrourological anomalies, nevus flammeus, ear malformations, hypoglycemia, hemihyperplasia, and organomegaly. BWS molecular defects, causing alteration of expression or activity of the genes regulated by two imprinting centres (IC) in the 11p15 chromosomal region, are also heterogeneous. In this paper we define (epi)genotype–phenotype correlations in molecularly confirmed BWS patients. The characteristics of 318 BWS patients with proven molecular defect were compared among the main four molecular subclasses: IC2 loss of methylation (IC2-LoM, n=190), IC1 gain of methylation (IC1-GoM, n=31), chromosome 11p15 paternal uniparental disomy (UPD, n=87), and cyclin-dependent kinase inhibitor 1C gene (CDKN1C) variants (n=10). A characteristic growth pattern was found in each group; neonatal macrosomia was almost constant in IC1-GoM, postnatal overgrowth in IC2-LoM, and hemihyperplasia more common in UPD (P<0.001). Exomphalos was more common in IC2/CDKN1C patients (P<0.001). Renal defects were typical of UPD/IC1 patients, uretheral malformations of IC1-GoM cases (P<0.001). Ear anomalies and nevus flammeus were associated with IC2/CDKN1C genotype (P<0.001). Macroglossia was less common among UPD patients (P<0.001). Wilms’ tumor was associated with IC1-GoM or UPD and never observed in IC2-LoM patients (P<0.001). Hepatoblastoma occurred only in UPD cases. Cancer risk was lower in IC2/CDKN1C, intermediate in UPD, and very high in IC1 cases (P=0.009). In conclusion, (epi)genotype–phenotype correlations define four different phenotypic BWS profiles with some degree of clinical overlap. These observations impact clinical care allowing to move toward (epi) genotype-based follow-up and cancer screening.

Cancer Risk in Beckwith-Wiedemann Syndrome: A Systematic Review and Meta-Analysis Outlining a Novel (Epi)Genotype Specific Histotype Targeted Screening Protocol.

OBJECTIVE To compare tumor risk in the 4 Beckwith-Wiedemann syndrome (BWS) molecular subgroups: Imprinting Control Region 1 Gain of Methylation (ICR1-GoM), Imprinting Control Region 2 Loss of Methylation (ICR2-LoM), Chromosome 11p15 Paternal Uniparental Disomy (UPD), and Cyclin-Dependent Kinase Inhibitor 1C gene (CDKN1C) mutation. STUDY DESIGN Studies on BWS and tumor development published between 2000 and 2015 providing (epi)genotype-cancer correlations with histotype data were reviewed and meta-analysed with cancer histotypes as measured outcome and (epi)genotype as exposure. RESULTS A total of 1370 patients with BWS were included: 102 developed neoplasms (7.4%). Tumor prevalence was 2.5% in ICR2-LoM, 13.8% in UPD, 22.8% in ICR1-GoM, and 8.6% in patients with CDKN1C mutations. Cancer ORs were 12.8 in ICR1-GoM, 6.5 in UPD, and 2.9 in patients with CDKN1C mutations compared with patients with ICR2-LoM. Wilms tumor was associated with ICR1-GoM (OR 68.3) and UPD (OR 13.2). UPD also was associated with hepatoblastoma (OR 5.2) and adrenal carcinoma (OR 7.0), and CDKN1C mutations with neuroblastic tumors (OR 7.2). CONCLUSION Cancer screening in BWS could be differentiated on the basis of (epi)genotype and target specific histotypes. Patients with ICR1-GoM and UPD should undergo renal ultrasonography scanning, given their risk of Wilms tumor. Alpha feto protein monitoring for heptaoblastoma is suggested in patients with UPD. Adrenal carcinoma may deserve screening in patients with UPD. Patients with CDKN1C mutations may deserve neuroblastoma screening based on urinary markers and ultrasonography scanning. Finally, screening appears questionable in cases of ICR2-LoM, given low tumor risk.

Thyroid Function Patterns at Hashimoto’s Thyroiditis Presentation in Childhood and Adolescence Are Mainly Conditioned by Patients’ Age

Background: There are few studies investigating the factors which may affect different biochemical presentations of Hashimoto’s thyroiditis (HT) and these are frequently based on limited pediatric populations. Aims: (1) To assess the frequency of thyroid function patterns at HT diagnosis in 608 children and adolescents, and (2) to analyze the factors that affect thyroid status at diagnosis. Results: At presentation, test results showed euthyroidism in 52.1% of patients (subgroup A), overt or subclinical hypothyroidism in 41.4%, and overt or subclinical hyperthyroidism in 6.5%. The mean age of patients with thyroid dysfunctions (subgroup B) was significantly lower than that of subgroup A, and the rate of children below 10 years of age was significantly greater in subgroup B. Other variables related to thyroid function patterns were prepubertal status; association with either Down or Turner syndromes, which correlated with increased risk of thyroid dysfunctions, and association with other autoimmune diseases, which correlated with decreased risk of thyroid dysfunctions. None of the remaining factors analyzed were associated with increased risk of thyroid dysfunctions. Conclusions: Biochemical thyroid function patterns at HT presentation in childhood and adolescence are mainly conditioned by patients’ age.

Frequency of Hashimoto's thyroiditis antecedents in the history of children and adolescents with graves' disease.

Background: The development of Graves’ disease (GD) from Hashimoto’s thyroiditis (HT) has sporadically been reported, but no data are available concerning the prevalence of this sequence of events in GD patients. Our aim was to ascertain HT antecedents in the history of GD children in order to assess for the first time the relative frequency of the event sequence leading from HT to GD in a pediatric population. Study Population and Results: In 105/109 patients, no HT antecedents were documented at GD presentation. The remaining 4 patients had previously exhibited a picture of HT with either hypothyroidism or euthyroidism. The interval between HT diagnosis and GD presentation ranged from 1.5 to 2.8 years. Serum thyrotropin receptor antibodies were higher in the patients with no HT antecedents. Conclusions: In at least 3.7% of the children with GD, hyperthyroidism may be preceded by HT presentation with either hypothyroidism or euthyroidism. The clinical course of GD in these patients is not different from the one observed in those with no HT antecedents. Our report confirms the existence of a continuum between HT and GD within the spectrum of autoimmune thyroid diseases.