Compound heterozygous and homozygous mutations of the TSHbeta gene as a cause of congenital central hypothyroidism in Europe.
BACKGROUND
Thyroid hormones are crucial for normal growth and central nervous system development. In recent years, germline variants of the TSHbeta subunit gene have been identified as a cause of congenital TSH deficiency.


METHODS
We performed a genetic and clinical study in children from four European countries diagnosed with congenital isolated central hypothyroidism.


RESULTS
TSHbeta gene analysis revealed compound heterozygosity for 145C-->T (Q49X) and 313delT (C105Vfs114X) in 1 infant and homozygous mutation 313delT (C105Vfs114X) in 5 patients. Although all presented with typical symptoms of hypothyroidism, diagnosis and treatment was delayed until 3-5 months in 5 of 6 patients. In a longitudinal sibpair analysis, thyroxine substitution initiated immediately after birth was effective to prevent developmental delay and growth retardation.


CONCLUSIONS
Clinical awareness is required to detect hypothyroidism due to TSHbeta mutations, which is not identified by TSH-based newborn screening. TSHbeta variants C105Vfs114X and Q49X are the most frequent cause of this severe disorder in Europe, now for the first time observed in compound heterozygous state.
University Children's Hospital, University of Ulm, Ulm, Germany. beate.karges@medizin.uni-ulm.de
Beate
B
Karges
Bruno
B
LeHeup
Eugen
E
Schoenle
Cintia
C
Castro-Correia
Manuel
M
Fontoura
Roland
R
Pfäffle
Werner
W
Andler
Klaus-Michael
KM
Debatin
Wolfram
W
Karges
D002648:Child; D002675:Child, Preschool; D003409:Congenital Hypothyroidism; D005060:Europe; D005192:Family Health; D005260:Female; D005838:Genotype; D018095:Germ-Line Mutation; D006130:Growth Disorders / Q000188:drug therapy / Q000517:prevention & control; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy / Q000235:genetics*; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D010375:Pedigree; D037322:Thyrotropin, beta Subunit / Q000172:deficiency / Q000235:genetics*; D013974:Thyroxine / Q000627:therapeutic use
D037322:Thyrotropin, beta Subunit; D013974:Thyroxine