{"title":"<i>THRB</i> Gene Mosaicism Confirmed by Next-Generation Sequencing in a Clinically Symptomatic Infant.","authors":"Jenny Yeuk Ki Cheng, Shreenidhi Ranganatha Subramaniam, Hoi Shan Leung, Sammy Wai Chun Wong, Jeffrey Sung Shing Kwok, Wai Kei Jacky Lam","doi":"10.1210/jcemcr/luae075","DOIUrl":null,"url":null,"abstract":"<p><p>A 4-day-old infant was admitted for neonatal jaundice. He had persistent tachycardia and tachypnea. Initial workup showed a serum free T4 of 75.6 pmol/L (5.87 ng/dL) (reference range: 11.5-28.3 pmol/L; 0.89-2.20 ng/dL) and a nonsuppressed TSH 3.76 mIU/L (reference range: 0.72-11.0 mIU/L). A TRH stimulation test showed an exaggerated TSH response with a peak of 92.1 mIU/L at 30 minutes after TRH injection, which suggested the diagnosis of resistance to thyroid hormone β syndrome. Sanger sequencing showed a questionable pathogenic variant in the <i>THRB</i> gene with low signal amplitude. Restriction fragment length polymorphism was consistent with its presence. The variant was originally reported as heterozygous. Next-generation sequencing was performed on blood and buccal swab samples of the patient and his parents, which confirmed this de novo mosaic variant NM_000461.5:c.1352T > C p.(Phe451Ser) in the patient but not in his asymptomatic parents. As it was in a mosaic state, only the offspring, but not other first-degree relatives, of the patient would have the risk of inheriting that variant.</p>","PeriodicalId":73540,"journal":{"name":"JCEM case reports","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11066914/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"JCEM case reports","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1210/jcemcr/luae075","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/5/1 0:00:00","PubModel":"eCollection","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
A 4-day-old infant was admitted for neonatal jaundice. He had persistent tachycardia and tachypnea. Initial workup showed a serum free T4 of 75.6 pmol/L (5.87 ng/dL) (reference range: 11.5-28.3 pmol/L; 0.89-2.20 ng/dL) and a nonsuppressed TSH 3.76 mIU/L (reference range: 0.72-11.0 mIU/L). A TRH stimulation test showed an exaggerated TSH response with a peak of 92.1 mIU/L at 30 minutes after TRH injection, which suggested the diagnosis of resistance to thyroid hormone β syndrome. Sanger sequencing showed a questionable pathogenic variant in the THRB gene with low signal amplitude. Restriction fragment length polymorphism was consistent with its presence. The variant was originally reported as heterozygous. Next-generation sequencing was performed on blood and buccal swab samples of the patient and his parents, which confirmed this de novo mosaic variant NM_000461.5:c.1352T > C p.(Phe451Ser) in the patient but not in his asymptomatic parents. As it was in a mosaic state, only the offspring, but not other first-degree relatives, of the patient would have the risk of inheriting that variant.