Identification of Novel Variants in MEN1: A Study Conducted with Four Multiple Endocrine Neoplasia Type 1 Patients

Genetic and Functional Analyses of the Novel KLF11 Pro193Thr Variant in a Three-Generation Family with MODY7

KLF11 regulates insulin gene expression through binding to the insulin promoter and has been reported as a causative gene for maturity-onset diabetes of the young 7 (MODY7). Here, we report a novel KLF11 variant associated with a three-generation family with early childhood-onset diabetes and explore its clinical and functional characteristics. The three-generational pedigree contains five patients affected by diabetes. The pathogenic variant identified by whole-exome sequencing was further confirmed by Sanger sequencing and pedigree verification. Luciferase reporter assays and glucose-stimulated insulin secretion were used to examine whether the KLF11 variant binds to the insulin promoter and regulate insulin secretion in vitro. The proband, his son, and his uncle exhibited hyperglycemia at ages 32, 13 and 71 years, respectively. All three patients showed characteristics of metabolic syndrome (obesity, dyslipidemia, and diabetes), but the insulin secretion of islet β-cells was impaired. A novel heterozygous missense variant, c.577 C>A (p.Pro193Thr) of the KLF11 gene was detected in all three patients. This variant co-segregates with the diabetes phenotype, consistent with an autosomal dominant disorder. The identified KLF11 p.Pro193Thr variant drastically decreased the transcriptional activity of KLF11, as demonstrated by luciferase reporter assay. Functional analyses revealed that the KLF11 Pro193Thr variant inhibited glucose-stimulated insulin secretion. We identified a novel KLF11 Pro193Thr variant in a three generation family with MODY7. These findings shed light on the molecular mechanisms underlying the pathogenesis of MODY7 and expand the genotype and clinical spectrum of MODY7.

Clinical and functional analyses of the novel STAR c.558C>A in a patient with classic lipoid congenital adrenal hyperplasia

Objective: Congenital lipid adrenal hyperplasia (LCAH) is the most serious type of congenital adrenal hyperplasia and is caused by steroid-based acute regulatory (STAR) protein mutations. Herein, we report compound heterozygous mutations c.558C>A (p.S186 R) and c.772C>T (p.Q258*) in a newborn 46 XY patient diagnosed with classic LCAH and explore their clinical and functional characteristics. Methods: Peripheral blood samples were collected from LCAH patient and their families. The pathogenic variant identified by whole-exome sequencing was further confirmed by Sanger sequencing and pedigree verification. The functional consequence and ability to convert cholesterol into progesterone of the identified STAR Q258* and S186 R mutations were analyzed by cell transfection and in vitro assays. Results: The proband was presented with severe glucocorticoid and mineralocorticoid deficiency, high adrenocorticotropic hormone, and enlarged adrenals. Heterozygous mutations p. S186 R and p. Q258* in the STAR gene were identified in the patient, and her parents were carriers, which is consistent with an autosomal recessive disorder. The STAR p. Q258* mutation has been reported and generates a truncated protein. The p. S186 R mutation is a novel variant that disrupts STAR. The residual STAR activities of p. S186R, p. Q258*, and p. S186R/p.Q258* were 13.9%, 7.3%, and 11.2%, respectively, of the wild-type, proving the main negative effects of the mutant proteins. Conclusion: Our findings reveal the molecular mechanisms underlying LCAH pathogenesis, further expanding the genotype and clinical spectrum of LCAH.

Different cell compositions and a novel somatic KCNJ5 variant found in a patient with bilateral adrenocortical adenomas secreting aldosterone and cortisol

INTRODUCTION

This study aimed to explore the possible pathogenesis of a rare case of co-existing Cushing's syndrome (CS) and primary aldosteronism (PA) caused by bilateral adrenocortical adenomas secreting aldosterone and cortisol, respectively.

METHODS

A 41-year-old Chinese woman with severe hypertension and hypokalemia for 5 and 2 years, respectively, was referred to our hospital. She had a Cushingoid appearance. Preoperative endocrinological examinations revealed autonomous cortisol and aldosterone secretion. Computed tomography revealed bilateral adrenal adenomas. Subsequently, adrenal vein sampling and sequential left and right partial adrenalectomy indicated the presence of a left aldosterone-producing tumor and a right cortisol-producing tumor. Pathological examination included immunohistochemical analysis of the resected specimens. Secretions of aldosterone and cortisol were observed both in vivo and in vitro. Further, whole-exome sequencing was performed for DNA that was extracted from peripheral blood leukocytes and bilateral adrenal adenomas in order to determine whether the patient had relevant variants associated with PA and CS.

RESULTS

Immunohistochemical staining revealed that the left adenoma primarily comprised clear cells expressing CYP11B2, whereas the right adenoma comprised both eosinophilic compact and clear cells expressing CYP11B1. The mRNA levels of steroidogenic enzymes (including CYP11B1 and CYP17A1) were high in the right adenoma, whereas CYP11B2 was highly expressed in the left adenoma. A novel somatic heterozygous missense variant-KCNJ5 c.503T > G (p.L168R)-was detected in the left adrenal adenoma, but no other causative variants associated with PA and CS were detected in the peripheral blood or right adrenocortical adenoma. In the primary cell culture of the resected hyperplastic adrenal adenomas, verapamil and nifedipine, which are two calcium channel blockers, markedly inhibited the secretion of both aldosterone and cortisol.

CONCLUSION

We present an extremely rare case of bilateral adrenocortical adenomas with distinct secretion of aldosterone and cortisol. The heterogeneity of the tumor cell compositions of aldosterone- and cortisol-producing adenoma (A/CPA) and somatic mutation of KCNJ5 may have led to different hormone secretions in the bilateral adrenal adenomas.

Identification of New Molecular Biomarkers in Ovarian Cancer Using the Gene Expression Profile

Ovarian cancer is a common cause of death among women worldwide. The current diagnostic and prognostic procedures available for the treatment of ovarian cancer are either not specific or are very expensive. Gene expression profiling has proved to be a very effective tool in the exploration of new molecular markers in patients with ovarian cancer, although the link between such markers and patient survival and clinical outcomes is still elusive. We are looking for genes that may function in the development and progression of ovarian cancer. The aim of our study was to evaluate the expression of selected suppressor genes (ATM, BRCA1, BRCA2), proto-oncogenes (KRAS, c-JUN, c-FOS), pro-apoptotic genes (NOXA, PUMA), genes related to chromatin remodeling (MEN1), and genes related to carcinogenesis (NOD2, CHEK2, EGFR). Tissue samples from 30 normal ovaries and 60 ovarian carcinoma tumors were provided for analysis of the gene and protein expression. Gene expression analysis was performed using the real-time PCR method. The protein concentrations from tissue homogenates were determined using the ELISA technique according to the manufacturers’ protocols. An increase in the expression level of mRNA and protein in women with ovarian cancer was observed for KRAS, c-FOS, PUMA, and EGFR. No significant changes in the transcriptional levels we observed for BRCA1, BRCA2, NOD2, or CHEK2. In conclusion, we suggest that KRAS, NOXA, PUMA, c-FOS, and c-JUN may be associated with poor prognosis in ovarian cancer.

Identification of a novel mutation in patients with type A insulin resistance syndrome

INTRODUCTION

Type A insulin resistance syndrome is a rare type of congenital insulin resistance often caused by heterozygous mutations in the insulin receptor gene (INSR). The aim of this study is to explore the clinical and genetic characteristics of three patients with type A insulin resistance syndrome from two Chinese families.

METHODS

The peripheral blood samples were collected from each family members. Whole-exome sequencing were performed on three patients.

RESULTS

Patient #1 was diagnosed with hyperinsulinemia at the age of 11 years and presented with hirsutism, acanthosis nigricans, and polycystic ovaries by 13 years. A heterozygous c.3470A > G mutation in the INSR gene was identified in patient #1. Patient #2 was a 13-year-old girl who presented with insulin resistance, polycystic ovary, and hyperandrogenemia. A novel c.3601C > G INSR mutation was identified in patient #2. Co-segregated analysis showed that the c.3601C > G mutation was also found in her father, who had hyperinsulinemia and diabetes mellitus, which was consistent with autosomal dominant inheritance. SIFT and PolyPhen-2 predicted that the c.3470A > G and c.3601C > G mutations in INSR had damaging effects.

CONCLUSION

Our study expands the genotypic and phenotypic spectrum of type A insulin resistance syndrome. Awareness of the clinical features coupled with INSR gene screening is key to early detection and active intervention.

Heterogeneity of the Clinical Presentation of the MEN1 LRG_509 c.781C>T (p.Leu261Phe) Variant Within a Three-Generation Family

Multiple neuroendocrine neoplasia type 1 (MEN1) is a rare genetic disorder with an autosomal dominant inheritance, predisposing carriers to benign and malignant tumors. The phenotype of MEN1 syndrome varies between patients in terms of tumor localization, age of onset, and clinical aggressiveness, even between affected members within the same family. We describe a heterogenic phenotype of the MEN1 variant c.781C>T (LRG_509t1), which was previously reported only once in a family with isolated hyperparathyroidism. A heterozygous missense variant in exon 4 of the gene was identified in the sequence of the MEN1 gene, i.e., c.781C>T, leading to the amino acid change p.Leu261Phe in a three-generation family. In the screened family, 5/6 affected members had already developed hyperparathyroidism. In the index patient and two other family members, an aggressive course of pancreatic neuroendocrine tumor (insulinoma and non-functioning neuroendocrine tumors) with dissemination was diagnosed. In the index patient, late diagnosis and slow progression of the disseminated neuroendocrine tumor have been observed (24 years of follow-up). The very rare variant of MEN1, LRG_509t1 c.781C>T /p.Leu261Phe (LRG_509p1), diagnosed within a three-generation family has a heterogenic clinical presentation. Further follow-up of the family members should be carried out to confirm the spectrum and exact time of clinical presentation.