FH-Sydney 1 and 2: Two novel frameshift mutations in exon 10 of the low-density lipoprotein receptor gene detected by heteroduplex formation

We report two novel frameshift mutations in exon 10 of the low-density lipoprotein receptor gene that lead to familial hypercholesterolemia in separate lineages. The lesions, FH-Sydney 1 and FH-Sydney 2, were detected by a modified heteroduplex analysis of exon-specific polymerase chain reaction (PCR) amplified DNA, and characterized at the molecular level by sequencing. Restriction enzyme digestion of PCR amplified DNA confirmed the presence of the mutant alleles in affected family members and their absence in nonaffected family members in both lineages. FH-Sydney 1 is a 4-bp duplication at position 1373, while FH-Sydney 2 is a 2-bp deletion at position 1478. The predicted result of both mutations is the premature truncation of the receptor at stop codons generated downstream of the mutations. Neither mutation was detected in a survey of 54 unrelated familial hypercholesterolemia patients. © 1994 Wiley-Liss, Inc.     

Spectrum of low density lipoprotein receptor mutations in Czech hypercholesterolemic patients

The aim of our study was to define mutations causing familial hypercholesterolemia (FH) phenotype in Czech hypercholesterolemic individuals. A combination of heteroduplex analysis, SSCP, DGGE, DNA sequencing and PCR/restriction analysis was used for this purpose. Molecular searching in the promoter region and coding sequence of the low density lipoprotein receptor (LDLR) gene in 130 patients from 68 unrelated families resulted in the identification of 37 sequence variations. Thirty of them are most likely disease causing mutations. Nineteen mutations were novel (two nonsense, five missense, six nucleotide(s) insertions and six nucleotide(s) deletions). Their pathological effect can be predicted on the basis of their position with respect to previously reported mutations with an estimated reduction of the receptor activity and/or premature termination of translation. These results expand our knowledge of mutations responsible for FH. Seven nucleotide variations were characterized as silent polymorphisms. © 2001 Wiley‐Liss, Inc.     

Urinary 5-hydroxy indole acetic acid as a test for early diagnosis of acute appendicitis

OBJECTIVES: Acute appendicitis (AA) is the most common abdominal emergency. The appendix has abundant serotonin containing cells. Upon inflammation, serotonin is released in the blood and converted into 5-HIAA (5-hydroxy indole acetic acid). Measurement of the urine 5-HIAA (U-5-HIAA) could be a reliable marker of inflammation of the appendix. We have compared the powers of test performance of spot U-5-HIAA and spot U-5-HIAA/creatinin with other routine laboratory tests used for the diagnosis of acute appendicitis. DESIGN AND METHODS: Urine, serum, and blood samples of 110 patients who were admitted and observed in the emergency units of two university hospitals were studied. 5-HIAA was measured using HPLC, C-reactive protein by immunoturbidometry, WBC by electronic cell counting, and urine creatinine by the Jaffe method. Diagnostic accuracy of the various tests was evaluated by receiver operating characteristic (ROC) analysis. FINDINGS: The mean of spot U-5-HIAA in 39 patients with AA (nongangrenous) was 32 +/- 2.6 micromol/L, which was much higher than the mean of 40 non-appendicitis patients (NA) (5.5 +/- 0.6), 10 follicular hyperplasia (7.5 +/- 2.1), and 50 healthy control cases (4.1 +/- 0.5) with P < 0.001. The concentration of U-5-HIAA in 21 patients with gangrenous appendicitis (GA) (13.8 +/- 2.1) was also higher than NA patients and healthy individuals but lower than AA cases (P < 0.05). Considering 10 micromol/L as the cutoff point, this test shows 84% sensitivity and 88% specificity, with 90% and 81% positive and negative predictive values, respectively. The area under ROC curve (AUC) of U-5-HIAA in the diagnosis of AA (AUC = 0.903) was much larger than AUCs of U-5-HIAA/Cr (0.787), WBC (0.703), and CRP (0.660). CONCLUSION:: Urinary secretion of 5-HIAA increases significantly in acute appendicitis and measurement of spot U-5-HIAA gives higher diagnostic accuracy than other routine laboratory tests. While the inflammation progresses to necrosis of the appendix, the concentration of 5-HIAA decreases. This decrease could be a warning sign of perforation of the appendix.     

家族性高胆固醇血症的临床研究——Ⅲ.家族性高胆固醇血症息者的心血管改变

本文对11例家族性高胆固醇血症患者进行了临床心血管改变的研究,发现二维超声心动图对观察和随访这些患者的心血管改变最敏感,且二维超声心动图改变,心绞痛症状和心血管杂音与患者年龄和血浆高密度脂蛋白胆固醇水平有一定的关系。     

A novel deletion in the low-density lipoprotein receptor gene in a patient with familial hypercholesterolemia from Petersburg

Fifty St. Petersburg patients with type IIa hyperlipoproteinemia were screened for the presence of structural rearrangements in the low-density lipoprotein receptor (LDLR) gene. One novel deletion of the length about 5 kilobases (kb) was found. This deletion seems to remove completely exons 4, 5, and 6 from the LDLR gene, coding for the largest part of the receptor ligand-binding domain. © 1993 Wiley-Liss, Inc.     

Comparative analysis of AKT and the related biomarkers in uterine leiomyomas with MED12, HMGA2, and FH mutations

Uterine leiomyomas (ULM) are histologically and molecularly heterogeneous and clinically they grow at vastly different rates. Several driver gene mutations have been identified in ULM, including MED12 mutations, HMGA2 overexpression, and biallelic FH inactivation. ULM with different driver mutant genes may use different molecular pathways, but currently no clear correlation between gene mutations and growth related pathways has been established. To better define this relationship, we collected ULM with MED12 (n = 25), HMGA2 (n = 15), and FH (n = 27) mutations and examined the sex steroid hormone, cell cycle, and AKT pathway genes by immunohistochemistry. While ER and PR were highly expressed in all types of ULM, FH ULM showed lower ER expression and higher PR expression. HMGA2 tumors had significantly higher levels of AKT signaling and mitogenic activity than other ULM types. HMGA2 activated AKT signaling through upregulation of IGF2BP2. Silencing HMGA2 in ULM cells resulted in downregulation of AKT and upregulation of p16 and p21, which eventually led to cell senescence. HMGA2 overexpression in ULM is not only related to tumor development but also plays a role in controlling cellular proliferation through the AKT pathway.     

COL4A4-related nephropathy caused by a novel mutation in a large consanguineous Saudi family

Introduction

Collagen type IV related nephropathies are due to the defects in collagen IV genes COL4A3, COL4A4, or COL4A5 and comprise a spectrum of phenotypes ranging from Alport Syndrome (AS) to its mild variants, termed as familial haematuria or thin basement membrane nephropathy. Classical AS is a progressive renal disease presenting with a triad of progressive hematuric nephritis and typical extra-renal complications, such as sensorineural hearing loss (SNHL) and variable ocular anomalies. The mode of inheritance in AS is X-linked in 85%, autosomal recessive in 15%, and autosomal dominant in rare cases.

Objectives

This study aims to identify underlying mutation in multiple individuals from a large consanguineous Saudi family with inherited nephropathy, including our index patient who manifested all the features of classical AS.

Patients and methods

Patients were diagnosed by nephrologists and clinical geneticists. All the individuals underwent clinical, audiological and ophthalmological evaluation. Blood samples were collected after written informed consent. DNA extraction, homozygosity mapping and PCR amplification followed standard methodologies.

Results

The disease locus was mapped to 2q36.3, where both COL4A3 and COL4A4 reside. Sanger sequencing of COL4A3 and COL4A4 revealed an underlying novel homozygous disease-causing COL4A4 mutation (c.2420delG; p.G807fsX60) in the affected proband. Considerable phenotypic variability segregating with this COL4A4 mutation in our study family is documented. The homozygous mutants were manifesting end-stage renal disease (ESRD) in their adolescence, while the heterozygous carrier members were presenting with considerable phenotypic heterogeneity ranging from intermittent hematuria to late onset ESRD. In addition, there is a relatively severe involvement of the ear (SNHL) and eye in the homozygotes than the heterozygotes. Fertility problems were also noted in both of the homozygous females.

Conclusion

Identification of the causative mutation is an efficient strategy for conclusive molecular diagnosis in the patients and to establish genotype/phenotype correlation. It is important to study and evaluate asymptomatic carriers, to predict prognosis of the disease and to obviate the need for another renal biopsy in at-risk related family members. While an accurate genetic diagnosis of AS provides valuable information for genetic counseling in the extended family members, it can also facilitate future prenatal diagnosis and planning for pre-implantation genetic diagnosis.