TY - JOUR
T1 - TGB deficiency
T2 - Description of two novel mutations associated with complete TBG deficiency and review of the literature
AU - Mannavola, Deborah
AU - Vannucchi, Guia
AU - Fugazzola, Laura
AU - Cirello, Valentina
AU - Campi, Irene
AU - Radetti, Giorgio
AU - Persani, Luca
AU - Refetoff, Samuel
AU - Beck-Peccoz, Paolo
PY - 2006/10
Y1 - 2006/10
N2 - Thyroxine-binding globulin (TBG) is the main thyroid hormone transport protein in serum. Inherited TBG defects lead to a complete (TBG-CD) or a partial (TBG-PD) deficiency and have a diagenic transmission, being clinically fully expressed only in hemizygous males and in homozygous females. In the present study, seven patients from two unrelated families with TBG-CD were studied and two novel TBG mutations were documented. In particular, a T insertion at the 5′ donor splice site of exon 0, between nucleotides 2 and 3 at the beginning of intron 1 (g.IVS1+2_3insT) was found in one family and was named TBG-Milano. The other novel mutation is a T deletion at nucleotide 214 of exon 1, which leads to a frameshift at codon 50 with a premature stop codon at position 51 (c.214delT, P50fsX51) and was named TBG-Nikita. According to the X-linked transmission of the defect, females harboring the mutation showed a reduction in TBG levels with normal TSH and total thyroid hormone values at the lower limit of normal. Males harboring either TBG-Milano or TBG-Nikita, showed normal TSH values and low levels of total thyroid hormones and lacked TBG. In conclusion, we report two novel mutations of the TBG gene associated with a complete TBG defect. The first mutation lies at the 5′ donor splice site of exon 0 and probably alters the start of translation, while the second is a single nucleotide deletion and leads to a premature stop codon.
AB - Thyroxine-binding globulin (TBG) is the main thyroid hormone transport protein in serum. Inherited TBG defects lead to a complete (TBG-CD) or a partial (TBG-PD) deficiency and have a diagenic transmission, being clinically fully expressed only in hemizygous males and in homozygous females. In the present study, seven patients from two unrelated families with TBG-CD were studied and two novel TBG mutations were documented. In particular, a T insertion at the 5′ donor splice site of exon 0, between nucleotides 2 and 3 at the beginning of intron 1 (g.IVS1+2_3insT) was found in one family and was named TBG-Milano. The other novel mutation is a T deletion at nucleotide 214 of exon 1, which leads to a frameshift at codon 50 with a premature stop codon at position 51 (c.214delT, P50fsX51) and was named TBG-Nikita. According to the X-linked transmission of the defect, females harboring the mutation showed a reduction in TBG levels with normal TSH and total thyroid hormone values at the lower limit of normal. Males harboring either TBG-Milano or TBG-Nikita, showed normal TSH values and low levels of total thyroid hormones and lacked TBG. In conclusion, we report two novel mutations of the TBG gene associated with a complete TBG defect. The first mutation lies at the 5′ donor splice site of exon 0 and probably alters the start of translation, while the second is a single nucleotide deletion and leads to a premature stop codon.
KW - TBG gene mutations
KW - TBG-CD
KW - TBG-PD
KW - Thyroid hormones
KW - Thyroxine-binding globulin defects
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U2 - 10.1007/s00109-006-0078-9
DO - 10.1007/s00109-006-0078-9
M3 - Article
C2 - 16947003
AN - SCOPUS:33749186774
VL - 84
SP - 864
EP - 871
JO - Journal of Molecular Medicine
JF - Journal of Molecular Medicine
SN - 0946-2716
IS - 10
ER -