A novel androgen receptor gene mutation in a Chinese patient with complete androgen insensitivity syndrome

Objective

To identify the underlying androgen receptor gene mutation in a Chinese patient with typical symptoms of complete androgen insensitivity syndrome.

Study design

A Chinese female phenotype with 46, XY karyotype was diagnosed because of primary amenorrhea. Mutations were determined by polymerase chain reaction followed by DNA sequencing.

Results

DNA sequencing of the androgen receptor gene showed a G2439T transition causing E442X mutation in exon 1 in the patient with complete androgen insensitivity syndrome. The E442X mutation was a new de novo non-sense mutation in exon 1 of the androgen receptor gene. This non-sense mutation is located in the N-terminal transactivation domain and leads to a predicted truncated protein of 441 amino acids with loss of the end part of the N-terminal transactivation domain, and the DNA-binding and ligand-binding domain.

Conclusion

This E442X non-sense point mutation has not been described previously in cases of androgen insensitivity syndrome, and could lead to the synthesis of a short truncated non-functional androgen receptor probably responsible for the phenotype of complete androgen insensitivity syndrome in the affected individual. Gonadectomy should be planned to eliminate the risk of gonadal malignancy.     

A unique point mutation in the androgen receptor gene in a family with complete androgen insensitivity syndrome.

OBJECTIVE: To further delineate the diversity of genetic alterations in the gene coding for the androgen receptor in individuals with the androgen insensitivity syndrome and to increase our understanding of the disease at the molecular level. DESIGN: This was a prospective study in which genomic deoxyribonucleic acid (DNA) from individuals with androgen insensitivity were examined through the polymerase chain reaction and DNA sequencing analysis. PATIENTS: Eleven complete and four individuals with partial androgen insensitivity syndrome were examined. RESULTS: Exons two through eight were grossly intact in all study subjects. Nucleotide sequence analysis revealed that three of three related family members with complete androgen insensitivity had the same guanine to adenine base substitution in exon five of the steroid-binding domain. CONCLUSION: The subsequent alanine to threonine amino acid conversion may have resulted in a configurational change of the androgen receptor protein leading to complete androgen insensitivity. This precise alteration has not been previously identified in the human androgen receptor gene in patients with the androgen insensitivity syndrome.     

A double nucleotide insertion-induced frame-shift mutation of the androgen receptor gene in a familial complete androgen insensitivity syndrome

Objective

A wide spectrum of androgen receptor (AR) gene mutations has been reported in complete androgen insensitivity syndrome (CAIS). The molecular basis of androgen resistance was investigated in a female with familial CAIS.

Study design

AR gene and protein were investigated by PCR and direct sequencing and Western immunoblotting, respectively.

Results

Sequencing analysis of DNA of the patient identified a double nucleotide insertion in exon 4 that results in the frame-shift leading to premature terminal signal in the beginning of exon 6. This mutation predicted the synthesis of a truncated AR that lacks the entire ligand-binding molecules. Immunoblotting analysis of the gonad removed from the patient detected the mutated AR protein of 94 kDa. Positive control revealed the normal apparent molecular mass of 110 kDa. DNA sequencing of her mother demonstrated the presence of both canonical and mutated sequences in the exon 4 through 8.

Conclusion

These findings suggested that the previously undescribed insertion mutation in the AR gene is the cause of CAIS in this family.     

A novel missense mutation C11994T in the mitochondrial ND4 gene as a cause of low sperm motility in the Indian subcontinent

We have analyzed the mitochondrial DNA of 34 oligoasthenozoospermic men along with 150 normozoospermic fertile men from the Indian subcontinent. A novel missense mutation (C11994T) in the ND4 gene, which replaces threonine with isoleucine, was observed in all of the oligoasthenozoospermic men but not in any of the normozoospermic fertile men.     

A novel heterozygous missense mutation 377T > C (V126A) of TGIF gene in a family segregated with holoprosencephaly and moyamoya disease

OBJECTIVES: To identify whether any mutations of candidate genes including SHH, ZIC2, SIX3, and TGIF exist in a Taiwanese family segregated with holoprosencephaly (HPE) and moyamoya disease. METHODS: Genotypes of the candidate genes SHH, ZIC2, SIX3, and TGIF were determined in the family members who were available for analysis by sequencing. In addition, genomic regions of another 50 unrelated Taiwanese (100 chromosomes) were studied to verify whether the nucleotide changes we found were mutations or polymorphisms. RESULTS: A novel missense mutation 377T > C and two polymorphisms (420A > G and 487C > T) in the TGIF gene were identified. No mutations in SHH, ZIC2 and SIX3 were found. The mother of the three HPE fetuses was found to be afflicted with moyamoya disease. A brief review of the mutations as well as polymorphisms reported in the TGIF gene up to 2005 is given. CONCLUSION: Molecular diagnosis can help genetic counseling in HPE, which is a heterogeneous disorder with its phenotypic and genotypic spectrum highly widened and variable. The possible association between TGIF mutation and moyamoya disease noted in our study also appeared to be novel.     

A novel mutation of the fibrillin-1 gene in a newborn with severe Marfan syndrome.

Marfan syndrome in the neonatal age represents a severe early and commonly lethal manifestation of Marfan syndrome, which is caused by mutations in the gene encoding fibrillin-1 (FBN1). Here, we report a newborn with severe Marfan syndrome and a novel mutation involving cysteine substitution within one of the epidermal growth factor-like domains of FBN1.     

Primary amenorrhea in a young Polish woman with complete androgen insensitivity syndrome and Sertoli-Leydig cell tumor: identification of a new androgen receptor gene mutation and evidence of aromatase hyperactivity and apoptosis dysregulation within the tumor.

Primary amenorrhea in 46,XY females can be due to complete androgen insensitivity syndrome (CAIS), pure gonadal dysgenesis, 17-hydroxysteroid dehydrogenase deficiency, or mixed gonadal dysgenesis. The present paper describes a new de novo non-sense mutation in exon 1 (K141Z) of the androgen receptor gene (AR) and the expression in CAIS testis of aromatase, estrogen receptors, as well as proliferation- and apoptosis-associated proteins. CAIS is a rare disease characterized by absent virilization in 46,XY individuals and the development of a female phenotype despite normal or even elevated androgen levels. CAIS is usually caused by a mutation in AR, which leads to organ resistance to androgens. Testicular tumors such as Sertoli-Leydig cell tumor often develop in patients with CAIS. The immunohistochemical findings in the testes of our CAIS patient suggest that the high expression of aromatase and other molecular changes in the testis may be responsible for pubertal breast development and the increased risk of testicular tumor.     

C825T polymorphism in the human G protein beta 3 subunit gene and preeclampsia; a case control study.

OBJECTIVE: Recently, a polymorphism of the gene encoding for the G protein beta3-subunit (GNB3) has been described. The T allele of this polymorphism (825T) is associated with endothelium dysfunction. Endothelium dysfunction has been described in women with preeclampsia. We, therefore, tested the hypothesis that in women who have had preeclampsia the T allele is more prevalent than in controls. STUDY DESIGN: We conducted a case-control study of 157 women with preeclampsia during 1991-1996. Cases and controls were tested for the presence of 825T by genotyping. Logistic regression methods were used for data analysis. RESULTS: The frequency of the T allele of the GNB3 gene was similar in cases (0.30) and controls (0.27) (odds ratio 1.24, 95% confidence interval 0.88-1.75). Compared to controls, we found a high frequency of the T allele in patients with the hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome (odds ratio 4.25, 95% confidence interval 1.12-16.05). CONCLUSION: The frequency of the T allele of the GNB3 gene, which serves as a marker for endothelium dysfunction, was not different between women with preeclampsia and controls. Women with the HELLP syndrome had a high frequency of the T allele. This suggests that this polymorphism in the GNB3 gene does not contribute to endothelium dysfunction in women with preeclampsia while it does contribute in women with the HELLP syndrome.     

A De Novo novel mutation of the EDNRB gene in a Taiwanese boy with Hirschsprung disease.

Hirschsprung disease (HSCR) is a congenital disorder characterized by an absence of ganglion cells in the nerve plexuses of the lower digestive tract. Although mutations in eight different genes (EDNRB, EDN3, ECE1, SOX10, RET, GDNF, NTN, SIP1) have been identified in affected individuals, it is now clear that RET and EDNRB are the primary genes implicated in the etiology of HSCR. All eight genes are involved in the early development of the enteric nervous system, and most act through two distinct biochemical pathways mediated by RET and EDNRB. Mutations in RET and EDNRB account for up to 50% and 5% of HSCR cases in the general population, respectively. Interaction between these two signaling pathways could modify RET expression and, therefore, HSCR phenotype. Here, we report the case of a 1-year-old Taiwanese boy who presented with abdominal distension since birth and bilious vomiting after feeding. HSCR (short-segment type) was diagnosed based on X-ray, lower gastrointestinal series and biopsy findings. Mutation analysis revealed a heterozygous T>C missense mutation in exon 1 of the EDNRB gene, that substitutes the highly conserved cysteine-90 residue in the extracellular domain of the G protein-coupled receptor with an arginine residue (C90R). No RET gene mutation was detected in this patient.     

Functional pulmonary atresia in a patient with neonatal Marfan syndrome caused by a c.3602G>A mutation in exon 29 of the FBN1 gene

Neonatal Marfan syndrome is a severe form of the syndrome mostly caused by de-novo mutations in the fibrillin-1 gene. We report a newborn with neonatal Marfan syndrome and functional pulmonary atresia who died from congestive heart failure on postnatal day 22 despite treatment. He had a mutation in exon 29 of the fibrillin-1 gene at position c.3602G>A. Functional pulmonary atresia may be a life-threatening cardiovascular manifestation of neonatal Marfan syndrome.