SERPINA7 Research Articles

Partial Thyroid Hormone-Binding Globulin Deficiency: A Case Report and Literature Review.

Thyroxine binding globulin (TBG) deficiency is a rare thyroid disease, mostly caused by genetic mutations and acquired by X-linked recessive inheritance. The clinical features of children with TBG deficiency and their family members were summarised and the Serpina7 gene mutation was analysed, providing a reference for the differentiation of TBG deficiency. Thyroid function was detected in TBG deficient patients, and genetic analysis was performed using polymerase chain reaction (PCR) and direct DNA sequencing to detect the characteristics of TBG mutants. Using "thyroxine binding globulin, gene and mutation" as keywords, PubMed (biomedical literature database), Web of Science and other databases were searched for relevant studies to collect and summarise relevant information. The TBG (14.7 μg/mL), 70% triiodothyronine (T3) (<0.3 nmol/L), total T3 (Tr3) (<0.05 ng/mL) and thyroxine (T4) (14.72 nmol/L) values were lower than normal, while the thyrotropin (TSH) (2.33 uIU/mL), free T3 (FT3) (1.62 pmol/L), and free T4 (FT4) (11.39 pmol/L) values were normal. These values indicate a TBG partially deficient phenotype. Using PCR amplification and direct sequencing of the target gene, a missense mutation in exon 4 of the Serpina7 gene was found in the patient and the father, and the nucleic acid variant was C.909 (exon 4) g > T; the patient was heterozygous and the father was hemizygous. The literature search retrieved a total of 45 studies, most of which were related to mutations in the Serpina7 gene. The mutation locations included exons, introns, enhancers and promoters, with exons the predominant location. A total of 49 variants of the Serpina7 gene were identified. Serpina7 C.909G (P.L303F) is a mutation acquired from the father by X-linked recessive inheritance. The main clinical features of TBG deficiency patients are low serum T4, T3 and TBG levels, normal TSH, FT3 and FT4 levels, and no clinical manifestations.

Identification of a novel mutation in thyroxine-binding globulin (TBG) gene associated with TBG-deficiency and its effect on the thyroid function.

This study presents a case of familial transmission of thyroxine-binding globulin (TBG) deficiency. The SERPINA7-gene which codes for TBG is located on the X-chromosome (Xq21-22). More than 45 mutations have been reported to cause TBG- deficiency from various countries, but none from India so far. Genetic analysis of SERPINA7 gene was carried out to determine the cause of low TBG levels in one family. DNA samples of the propositus and the family members were subjected to Polymerase Chain Reaction (PCR) followed by direct sequencing. Allele-specific PCR and Next-gen sequencing (NGS) were employed to confirm the site of the mutation. Thyroid function tests were estimated by Radioimmunoassay (RIA) and Immunoradiometric assay (IRMA) kits. X-chromosomal inactivation status was analyzed in the female members harboring the mutation. A mutational screening in this family revealed a novel frame-shift mutation S353Q, 354fs3X in the exon 4 ofthe SERPINA7gene which will be referred to as TBG-complete deficiency-India (TBG-CD-Ind). One out of four female family members harboring the mutation showed selective X-chromosomal inactivation. The affected family members were clinically euthyroid initially, showed changes in the thyroid function when tested after a long time span. However, the changes in the thyroid function in the affected family members had an autoimmune etiology. This study presents the first report of TBG-CD from India wherein a novel frameshift mutation referred to as TBG-CD-Ind (S353Q, 354fs3X)in the SERPINA7 gene was detected. No apparent association was identified between thyroid function and the TBG-mutation in the affected subjects. A detailed biochemical and genomic testing to determine the exact cause of discordant TFT in the patients would certainly aid in the unequivocal diagnosis of the thyroid function and for the precise individualized treatment.

Proteomic Analysis of Maternal Urine for the Early Detection of Preeclampsia and Fetal Growth Restriction.

Background: To explore the use of maternal urine proteome for the identification of preeclampsia biomarkers. Methods: Maternal urine samples from women with and without preeclampsia were used for protein discovery followed by a validation study. The targeted proteins of interest were then measured in urine samples collected at 20–24 and 30–34 weeks among nine women who developed preeclampsia, one woman with fetal growth restriction, and 20 women with uncomplicated pregnancies from a longitudinal study. Protein identification and quantification was obtained using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Results: Among the 1108 urine proteins quantified in the discovery study, 21 were upregulated in preeclampsia and selected for validation. Nineteen (90%) proteins were confirmed as upregulated in preeclampsia cases. Among them, two proteins, ceruloplasmin and serpin A7, were upregulated at 20–24 weeks and 30–34 weeks of gestation (p < 0.05) in cases of preeclampsia, and could have served to identify 60% of women who subsequently developed preeclampsia and/or fetal growth restriction at 20–24 weeks of gestation, and 78% at 30–34 weeks, for a false-positive rate of 10%. Conclusions: Proteomic profiling of maternal urine can differentiate women with and without preeclampsia. Several proteins including ceruloplasmin and serpin A7 are upregulated in maternal urine before the diagnosis of preeclampsia and potentially fetal growth restriction.

The decrease of T3 / T4 is not hypothyroidism - a new mutation of Serpina7 gene results in partial thyroglobulin deficiency.

To explore an unusual cause of the decrease of T3/T4 through a new mutation of TBG gene in a family, so as to avoid habitual thinking and reduce subsequent over treatment. TSH, free total T4, T3 and free T4, T3 were determined by automatic chemiluminescence immunoassay. The TBG mutation was identified by direct DNA sequencing. A frameshift mutation of p. l372ffs * 32 was found in the TBG gene (c.1114delc) of the patient by direct DNA sequencing, and the proband of the family was heterozygous. In vitro expression showed that the affinity of TBG for T4 decreased. Further examination of the family members showed that T3 and T4 were decreased, while FT3, FT4 and TSH were normal. If the patients with low TT4 and TT3 but normal TSH are found, the serum TBG level and related genes should be detected to determine whether it is TBG deficiency and avoid wrong treatment.

Thyroxine-binding globulin deficiency due to a novel SERPINA7 mutation: Clinical characterization, analysis of X-chromosome inactivation pattern and protein structural modeling

ObjectiveThyroxine-binding globulin (TBG) is the major human thyroid hormone transport protein, encoded by the SERPINA7 gene (Xq22.2). We aim to investigate the molecular basis of partial TBG deficiency (TBG-PD) in a female, by evaluating the X-chromosome inactivation pattern as well as the mutant protein structural modeling. Design and methodsSequencing of the coding region of the SERPINA7 gene was performed in a female with a TBG-PD phenotype and her first-degree relatives. The proband presented with low serum levels of total T3 (TT3) and total T4 (TT4), serum TSH level of 5.4 μUI/mL (normal range, 0.35–5.5), and serum TBG level of 5.5 mg/L (normal range, 13.6–27.2). X-chromosome inactivation pattern was evaluated by methylation analysis of the androgen receptor gene (Xq11.2). Structural analysis of the SERPIN family was performed using Pymol and Areaimol, and PFSTATS for conservation analysis and family-wide investigation of equivalent positions in human homologs. Modeller was used for point mutation structural modeling. ResultsA novel missense SERPINA7 mutation (p.R35W; c.163C > T) was found in heterozygosity in the proband, and in hemizygosity in her affected siblings. The proband X-chromosome inactivation ratio was 20:80. The substitution of an arginine by a tryptophan is predicted to disrupt the protein surface and main electrostatic interactions. Tryptophans are extremely rare (0.1%) in this position. ConclusionsWe report a new SERPINA7 variant associated with TBG-PD in three siblings. We named this variant TBG-Brasilia. The X-chromosome inactivation pattern may have accounted for the rare phenotypic expression in a female. The hydrophobic nature of the mutant is predicted to create an apolar patch at the surface, which results in protein aggregation and/or misfolding, potentially responsible for thyroid hormone transport defect.

A novel variant in the SERPINA7 gene causing partial TBG deficiency in a women and two male siblings: molecular and protein structural analysis

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Novel Mutation p.A64D in the Serpina7 Gene as a Cause of Partial Thyroxine-binding Globulin Deficiency Associated with Increases Affinity in Transthyretin by a Known p.A109T Mutation in the TTR Gene

Partial thyroxine-binding globulin deficiency (TBG-PD) is an endocrine defect with a prevalence of 1:4 000 in newborns. Due to the presence of a single TBG gene on the X chromosome, most familial TBG defects follow an X-linked inheritance pattern. Abnormal T4 binding to T4-binding prealbumin (TTR) is a rare cause of euthyroid hyperthyroxinemia, which is transmitted by autosomal dominant inheritance. The purpose of the present study was to identify and characterize new mutations in the Serpina7 and TTR genes in a complete family with typical TBG-PD. All patients underwent clinical and biochemical evaluation. Sequencing of DNA, population screening by (SSCP) analysis, and bioinformatics studies were performed. Molecular studies revealed a novel p.A64D mutation in the exon 1 of Serpina7 gene associated with the previously reported p.A109T mutation in the exon 4 of TTR gene. To our knowledge, this is the first report of a patient with a TBG-PD by a mutation in Serpina7 that was coincident with a mutation in TTR gene that increased affinity of TTR for T4. This work contributes to elucidate the molecular basis of the defects of thyroid hormone transport in serum and the improvement of the diagnosis avoiding unnecessary therapy.

A novel variant in Serpina7 gene in a family with thyroxine-binding globulin deficiency

Thyroxine-binding globulin (TBG) carries approximately 75% of serum T4 and T3. This protein is encoded by serpina7 gene, formerly known as TBG gene, localized on X-chromosome (Xq22.2). A deficiency in TBG is suspected when abnormally low serum total T4 and T3 are encountered in clinically euthyroid subjects in the presence of normal serum TSH. This condition has been associated with different serpina7 gene mutations resulting in amino acid substitutions or truncations in the mature protein. Herein, we report a new serpina7 gene variant in three members of the same family. It results in the replacement of the normal asparagine 233 by isoleucine and, subsequently, in disruption of a glycosylation site. Co-segregation of this new variant with undetectable levels of TBG in the hemizygous man studied and failure to recognize the same variant in 100 alleles at random, made us to consider it as the underlying cause of the TBG deficiency.

Mutatuion in the porcine SERPINA7 gene and its association with boar fertility

The porcine SERPINA7 gene is considered as a positional candidate gene responsible for testis size for its location on X chromosome and its biologically critical role in the development of testis. A nonsynonymous polymorphism (His226Asn or C678A) in the ligand-binding domain of SERPINA7 has been identified, which alters SERPINA7's affinity to thyroxine and is closely associated with testis size. In this study, a primer mutagenesis strategy was developed to genotype this polymorphism in Chinese indigenous pigs and some western commercial pigs. The C allele existed in all tested Chinese indigenous and wild pigs, while the A allele is specific for western commercial breeds, indicating the occurrence of the mutation is of western origin. The correlation of this polymorphism with different boar fertility traits was assessed using a White Duroc X Erhualian intercross which included 110 F2 mature boars. The results showed that the C678A polymorphism was closely associated with testis weight and epididymis weight ( P 0.0001 and P = 0. 0016, respectively) with significant heavier testis weight and epididymis weight in boars carrying the A allele than boars with the C allele. A significant correlation was also observed between this polymorphism and total sperm in the ejaculate (P0.01) as well as semen volume (P0.05). No statistically significant association of the C678A polymorphism with sperm concentration and sperm motility was found.