Understanding, Diagnosis and Monitoring of Thyroid Hormone Action Defects

Official title

Advancing Understanding, Diagnosis and Monitoring of Thyroid Hormone Action Defects (ADAM-THAD)

Overview

The goal of this observational study is to learn about the neurological and cardiological phenotype of patients with resistance to thyroid hormone (RTH) syndromes beta and alpha (RTHß and RTHa) due to dominant negative variants in the genes encoding the thyroid hormone receptors alpha (THRA) and beta (THRB). The main question\[s\] it aims to answer are: * Define frequency and improve early diagnosis for RTH syndromes * Developing tools to accelerate diagnosis of RTH syndromes * Development and validation of monitoring tools Participants, recruited at neonatal screening or from cohorts of patients with unexplained specific neuro-cognitive or cardiovascular phenotypes will be submitted to biochemical and genetic investigations. In addition pluripotent stem cells will be generated from peripheral blood cells of RTHs patients and studied in vitro to understand the molecular mechanisms underlying neurological and cardiovascular consequences. In vitro and clinical data, will be correlated to identify biomarkers for monitoring treatment.

Detailed description

TH action defects (THAD) are a group of rare syndromes characterized by abnormal thyroid hormone (TH) cell signaling due to defective transport, metabolism or action of TH via binding with nuclear receptors (TRs): there are two TRs, the alpha (TRa) and beta (TRß) receptors. Among them, mutations of THRA or THRB genes cause two distinct syndromes with Resistance to Thyroid Hormone (RTH) action whose incidence was estimated 1:20,000-50,000 newborns, likely representing the most frequent THAD forms. RTHa is due to dominant negative (DN) heterozygous mutations in THRA and characterized by dramatic manifestations in TRa-expressing tissues resembling untreated congenital hypothyroidism (CH).

RTHß is due to DN heterozygous THRB mutations, which cause variable TH resistance in TRß-expressing tissues (hypothalamus, pituitary, liver), resulting in distinctive biochemical signature (high free TH and unsuppressed TSH) together with additional features like deafness, impaired color vision and thyrotoxic-related symptoms (goiter, tachyarrhythmias, osteoporosis, anxiety and Attention-Deficit/Hyperactivity Disorder, ADHD).

Outstandingly, early treatment with TH or its analogues is expected to reduce most of the adverse consequences of RTHs but early/neonatal diagnosis is presently not feasible due to the lack of accurate biomarkers. Indeed, uniform characterization is essential for a rare disease, and establishment of clear-cut endocrine fingerprints for RTHa and RTHß are essential for a timely diagnosis.

In addition, the wide application of next generation sequencing (NGS) has yielded an unprecedented wealth of genetic information, calling for proper instruments to distinguish benign from pathogenic variants.

Finally, biomarkers for monitoring treatment of these conditions have not been established or validated.

This study aim to:

1. develop neonatal screening strategies for THAD and give unprecedented epidemiological characterization of RTHs in Italy 2. understand the pathogenicity of newly discovered THRB or THRA variants in in vivo model or identify new mechanisms 3. generate induced pluripotent stem cells from RTH patients to understand the molecular mechanisms underlying neurological and cardiovascular consequences and correlate in vitro and clinical data, with the final goal to identify potential biomarkers for monitoring treatment of these rare diseases.

Interventions

• Genetic NGS sequencing
  analysis of candidate genes for RTHs syndromes, transporters defects or gene involved in thyroid hormone metabolism. Whole exome sequencing (WES) in a minority of cases
• Diagnostic test serological tests
  assessment of T4, T3 and other TH metabolites (LC-MS) in serum and dried blood spots

Primary outcome measures

• Number of Newborns With Abnormal Thyroid Hormone Levels Suggestive of Resistance to Thyroid Hormone (RTH) Syndromes, as Measured in Dried Blood Spots (DBS). [Time frame: two years]
• Frequency of Phenotypic Changes in Zebrafish Zygotes Microinjected with Human TR Variants, as a Measure of the Functional Impact of THRA and THRB Variants of Uncertain Significance (VUS). [Time frame: two years]
• Direct differentiation of THRA mutant patients-derived human induced pluripotent stem cells (hiPSCs) to neural progenitors (hiPSc-CNeu) and cardiomyocyte (hiPSC-CMs) [Time frame: two years]
• To identify TH-target genes involved in determining stemness, proliferation potential and differentiation of hiPSC [Time frame: two years]

Secondary outcome measures (2)

• Prevalence of Resistance to Thyroid Hormone (RTH) Syndromes in Specific Cohorts of Patients with Unexplained Phenotypes [Time frame: two years]
• Generation of a comprehensive RTH database [Time frame: two years]

Eligibility criteria

Inclusion criteria

\- biochemical signature suggestive of RTHs syndromes at birth (a) or symptoms suggestive of RTHs syndromes (b) or known diagnosis of RTHs syndromes (c)

Exclusion criteria

• none

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Observational model

Case-only

Study locations

Italy · 2 centers

• Istituto Auxologico Italiano IRCCS — Milan
• Department of Endocrine & Metabolic Diseases, San Luca Hospital — Milan

Identifiers

NCT: NCT06307990 · 05M202

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗