Thyroid dyshormonogenesis is characterized by impairment in one of the several stages of thyroid hormone synthesis and accounts for 10%–15% of congenital hypothyroidism (CH). Seven genes are known to be associated with thyroid dyshormonogenesis: SLC5A5 (NIS), SCL26A4 (PDS), TG, TPO, DUOX2, DUOXA2, and IYD (DHEAL1). Depending on the underlying mechanism, CH can be permanent or transient. Inheritance is usually autosomal recessive, but there are also cases of autosomal dominant inheritance. In this review, we describe the molecular basis, clinical presentation, and genetic diagnosis of CH due to thyroid dyshormonogenesis, with an emphasis on the benefits of targeted exome sequencing as an updated diagnostic approach.
Congenital Hypothyroidism ; Diagnosis ; Exome ; Genetics* ; Thyroid Gland* ; Wills

OBJECTIVE: To study the types and characteristics of TUBB1 mutation in children with congenital hypothyroidism (CH) and thyroid dysgenesis (TD) in Shandong, China. METHODS: Mutations of the whole coding region of the TUBB1 gene were analyzed for 289 children with CH and TD in Shandong. Whole-genome DNA was extracted from peripheral blood leukocytes. PCR multiplication was performed for the whole coding region of the TUBB1 gene. Sanger sequencing was performed for the PCR products, and a biological information analysis was performed. RESULTS: Among the 289 children with CH and TD, 4 (1.4%) were found to have a c.952C>T(p.R318W) heterozygous mutation in the TUBB1 gene, resulting in the change of tryptophan into arginine at codon 318 of TUBB1 protein. This mutation was evaluated as "potentially pathogenic" based on the classification criteria and guidelines for genetic variation by American College of Medical Genetics and Genomics. CONCLUSIONS A novel mutation is detected in the exon of the TUBB1 gene in children with CH and TD in Shandong, suggesting that the TUBB1 gene may be a candidate pathogenic gene for CH children with TD.
Child ; China ; Congenital Hypothyroidism ; genetics ; DNA Mutational Analysis ; Humans ; Mutation ; Thyroid Dysgenesis ; genetics ; Tubulin ; genetics

OBJECTIVETo investigate the characteristics of DUOXA2 gene mutation and the genotype-phenotype relationship in children with congenital hypothyroidism (CH) in Guangzhou, China.

METHODSA total of 20 CH patients with suspected thyroid dyshormonogenesis who had no DUOX2 gene mutation were enrolled. These patients who were born between 2011 and 2012 were screened and diagnosed with CH in the Guangzhou Newborn Screening Center. PCR and direct sequencing were used to analyze DUOXA2 gene mutation.

RESULTSAmong the 20 patients, 2 had p.Y246X/p.Y246X homozygous mutation; 4 had monoallelic heterozygous mutation, among whom 2 carried the known pathogenic mutation c.413-414insA, 1 carried p.Y246X, and 1 carried a novel mutation, p.G79R. Reevaluation was performed at the age of 2-3 years, and the results showed that the two patients with p.Y246X/p.Y246X homozygous mutation were manifested as transient and mild permanent CH, respectively. Among the four patients with monoallelic heterozygous mutation, the one who carried p.Y246X mutation was manifested as typical permanent CH, and the other three were manifested as transient CH.

CONCLUSIONSDUOXA2 gene mutation is a common molecular pathogenic basis for CH children with suspected thyroid dyshormonogenesis in Guangzhou, and most of them are manifested as transient CH. There is no association between DUOXA2 genotypes and phenotypes. The novel mutation p.G79R is probably a pathogenic mutation.

Congenital Hypothyroidism ; genetics ; Female ; Genotype ; Humans ; Infant, Newborn ; Male ; Membrane Proteins ; genetics ; Mutation ; Phenotype

OBJECTIVE: To carry out variant analysis for a Chinese boy featuring dyshormonogenesis due to congenital hypothyroidism. METHODS: DNA of the patient and his parents was extracted and sequenced by high-throughput sequencing. The results were validated with Sanger sequencing and analyzed with Bioinformatics software. RESULTS: Sequencing result showed that the patient has carried compound variants of c.2654G>T(p.Arg885Leu) and c.943G>T(p.Gly315X) of the DUOX2 gene, which were inherited respectively from his mother and father. CONCLUSION The missense mutation c.2654G>T and nonsense mutation c.943G>T probably underlie the disease in this child.
Child ; Congenital Hypothyroidism ; diagnosis ; genetics ; Dual Oxidases ; genetics ; High-Throughput Nucleotide Sequencing ; Humans ; Male ; Mutation, Missense

OBJECTIVES: To analyze the results of neonatal screening for congenital hypothyroidism (CH) and hyperphenylalaninemia (HPA) in Zhejiang province from 1999 to 2022. METHODS: A total of 11 922 318 newborns were screened from September 1999 and December 2022 in Zhejiang province. The blood thyroid stimulating hormone (TSH) levels were measured by a fluorescence method and blood phenylalanine (Phe) levels were measured by fluorescence method or tandem mass spectrometry. TSH≥9 μIU/mL was considered positive for CH, while Phe>120 μmol/L and/or Phe/Tyr ratio>2.0 were considered positive for HPA. The positive newborns in screening were recalled, and the gene variations were detected by high-throughput sequencing and MassARRAY tests. RESULTS: The overall neonatal screening rate during 1999-2022 was 89.41% (11 922 318/13 333 929) and the screening rate was increased from 6.46% in 1999 to 100.0% in 2022. A total of 8924 cases of CH were diagnosed among screened newborns with an incidence rate of 1/1336. A total of 563 cases of HPA were diagnosed, including 508 cases of classic phenylketonuria (cPKU) and 55 cases of tetrahydrobiopterin deficiency (BH4D), with an incidence rate of 1/21 176. Ninety-seven out of 8924 cases of CH underwent genetic analysis. Gene mutations were detected in 9 CH related genes, the highest frequency mutations were found in DUOX2 gene (69.0%) with c.3329G>A (p.R1110Q) (18.2%) and c.1588A>T (p.K530X) (17.3%) as the hotspot mutations. There were 81 PAH gene variants detected in a total of 250 cases of cPKU, and c728G>A (p.R243Q) (24.4%), c.721C>T (p.R241C) (15.0%) were the hotspot mutations. Meanwhile 7 novel variants in PAH gene were detected: c.107C>A (p.S36*), c.137G>T (p.G46V), c.148A>G(p.K50E), c.285C>T (p.I95I), c.843-10delTTCC, exon4-7del and c.1066-2A>G. There were 12 PTS gene variants detected in 36 cases of BH4D, and c.259C>T (p.P87S) (31.9%) was the hotspot mutation. CONCLUSIONS The incident of CH has increased from 1999 to 2022 in Zhejiang province, and it is higher than that of national and global levels; while the incidence of HPA is similar to the national average. DUOX2 gene variation is the most common in CH patients; c.728G>A (p.R243Q) is the hotspot mutation in cPKU patients, while c.259C>T (p.P87S) is the hotspot mutation in BH4D patients.
Humans ; Infant, Newborn ; Neonatal Screening ; Dual Oxidases ; Congenital Hypothyroidism/genetics* ; Phenylketonurias/genetics* ; Thyrotropin

Case-Control Studies ; Child, Preschool ; Congenital Hypothyroidism ; DNA ; genetics ; Female ; Humans ; Hypothyroidism ; genetics ; Infant ; Iodine ; metabolism ; Male ; Mutation ; Polymerase Chain Reaction ; Sodium ; metabolism ; Symporters ; genetics

OBJECTIVE: To analyze the clinical phenotype and genetic etiology for a child featuring congenital hypothyroidism (CH). METHODS: Whole exome sequencing (WES), copy number variation (CNV) sequencing and chromosomal microarray analysis (CMA) were carried out for a newborn infant who had presented at Linyi People's Hospital for CH. Clinical data of the child was analyzed, in addition with a literature review. RESULTS: The main characteristics of the newborn infant had included peculiar face, vulvar edema, hypotonia, psychomotor retardation, recurrent respiratory tract infection with laryngeal wheezing and feeding difficulties. Laboratory test indicated hypothyroidism. WES suggested a CNV deletion on chromosome 14q12q13. CMA further confirmed a 4.12 Mb deletion at chromosome 14q12q13.3 (32649595_36769800), which has encompassed 22 genes including NKX2-1, the pathogenic gene for CH. The same deletion was found in neither of her parents. CONCLUSION Through the analysis of clinical phenotype and genetic variant, the child was diagnosed with 14q12q13.3 microdeletion syndrome.
Female ; Humans ; Congenital Hypothyroidism/genetics* ; DNA Copy Number Variations ; Phenotype ; Syndrome ; Microarray Analysis

OBJECTIVE: To explore the genetic basis for a child suspected for Say-Barber-Biesecker-Young-Simpson syndrome. METHODS: Genomic DNA was extracted from peripheral blood samples of the child and her parents. Whole exome sequencing was carried out for the proband. Suspected variants were validated by Sanger sequencing. The impact of the variants was predicted by bioinformatic analysis. RESULTS: The child was found to harbor a de novo missense variant c.2623C>T (p.Asp875Tyr) in exon 13 of the KAT6B gene. The variant was previously unreported, and was not recorded in the major allele frequency database and predicted to be pathogenic based on PolyPhen-2, MutationTaster and PROVEAN analysis. As predicted by UCSF chimera and CASTp software, the variant can severely impact the substrate-binding pocket of histone acetyltransferase, resulting in loss of its enzymatic activity. Based on standards and guidelines by the American College of Medical Genetics and Genomics, the variant was classified to be likely pathogenic (PS2+PM2+PP3). CONCLUSION The child's condition may be attributed to the de novo missense c.2623C>T (p.Asp875Tyr) variant of the KAT6B gene.
Blepharophimosis ; Child ; Congenital Hypothyroidism ; Facies ; Female ; Heart Defects, Congenital ; Histone Acetyltransferases/genetics* ; Humans ; Intellectual Disability ; Joint Instability ; Mutation ; Phenotype

Brain-lung-thyroid syndrome is a rare autosomal dominant disorder. More than 100 cases have been reported worldwide, but few cases have been reported in China. In December 2018, a boy with brain-lung-thyroid syndrome, aged 3 years and 10 months, was admitted to Xiangya Hospital of Central South University due to repeated cough for more than 3 years. In infancy of the boy, psychomotor retardation, repeated cough, and hypothyroidism were found. Gene detection showed that there was c.927delc heterozygous variation in NKX2-1 gene (NM-001079668: exon3: c.927delC). The variation of this gene locus has not been reported in relevant literature so far, which indicates a new mutation. According to the above clinical manifestations and examination results, the boy was diagnosed as brain-lung-thyroid syndrome, which mainly characterized by nervous system disorders, accompanied by respiratory manifestations and hypothyroidism. The boy was treated with oral dopasehydrazine to relieve tremor and levothyroxine sodium tablets to relieve hypothyroidism. Anti-infection, atomization, rehabilitation training and other symptomatic supporting treatment were also administered. The boy's language and movement have improved, the thyroid hormone level is normal, and there are still repeated respiratory tract infections.
Athetosis/genetics* ; Chorea ; Congenital Hypothyroidism/genetics* ; Cough ; Humans ; Male ; Respiratory Distress Syndrome, Newborn ; Thyroid Nuclear Factor 1/genetics*

Congenital hypothyroidism (CH), which results from insufficient thyroid hormone biosynthesis, is one of the most common neonatal endocrine disorders. Thyroid dysgenesis and thyroid dyshormonogenesis are the two causes of CH and either one will lead to deficiencies of enzymes during thyroid hormone biosynthesis and insufficient thyroid hormone biosynthesis. Recently, researchers have performed extensive studies on genetics of CH. This paper reviews genes reported to be associated with CH in China.
Congenital Hypothyroidism ; genetics ; Humans ; Iodide Peroxidase ; genetics ; Membrane Proteins ; genetics ; PAX8 Transcription Factor ; genetics ; Receptors, Thyrotropin ; genetics ; Thyroglobulin ; genetics ; Transcription Factors ; genetics