[Identification of pathogenic mutations in two Chinese families affected with primary localized cutaneous amyloidosis].

OBJECTIVE To identify potential mutations in two Chinese families affected with primary localized cutaneous amyloidosis. METHODS Peripheral blood samples of the family were collected with informed consent. Genomic DNA was extracted with a phenol chloroform method. All of the 17 exons and their flanking splicing sites of the OSMR gene were amplified with PCR and subjected to Sanger sequencing. Suspected mutations were verified with PCR - restriction fragment length polymorphism and high-resolution melting assays. RESULTS A missense mutation (c.1538G>A) was found in exon 10 of the OSMR gene in all of the six patients from family 1. A missense mutation (c.2081C>T) was found in exon 14 of the OSMR gene in all of the four patients from family 2. The same mutations were not found among the healthy controls. CONCLUSION Two missense mutations (c.1538G>A and c.2081C>T) were detected in the OSMR gene in two Chinese families affected with primary localized cutaneous amyloidosis. Our findings have further confirmed the pathogenicity of such mutations.

Mutational Spectrum of the MEFV Gene in AA Amyloidosis Associated With Familial Mediterranean Fever.

INTRODUCTION: Familial Mediterranean fever (FMF) is a recessively inherited disease which is characterized by recurrent episodic fever, abdominal pain, and polyserositis. It is caused by mutations in the MEFV gene, encoding the pyrin protein. The most important complication of FMF is secondary (AA) amyloidosis that leads to kidney failure. This study aimed to identify the frequency and distribution of MEFV mutations in Turkish patients with FMF-associated AA amyloidosis. MATERIALS AND METHODS: A total of 57 patients with FMF-associated AA amyloidosis and 60 healthy controls were included in this study. We analyzed the MEFV gene for E148Q, M694V, M680I, and V726A mutations and R202Q variant by polymerase chain reaction and restriction fragment length polymorphism methods.  Results. The male-female ratio was 0.72. The mean age of the patients was 29.8 ± 12.8 years. Among the patients, the rate of the MEFV mutations was found to be 77.2%. The most frequently observed genotype was homozygous M694V mutation, which was present in 17 patients (29.8%, P < .001), followed by compound heterozygous M680I/M694V (14.3%, P = .01). The R202Q allele frequencies were significantly different between patients and control group (P = .02; odds ratio, 0.53; 95% confidence interval, 0.30 to 0.94). CONCLUSIONS: In this study, mutation analysis of MEFV gene confirmed that the most frequent mutation was homozygous M694V genotype. R202Q may be important in patients with FMF-associated AA amyloidosis. Thus, it is suggested that investigation of R202Q should be considered as a genetic test for Turkish FMF patients.

Spectrum of Clinical Signs and Genetic Characterization of Gelatinous Drop-Like Corneal Dystrophy in a Colombian Family.

PURPOSE: To describe the clinical signs of gelatinous drop-like corneal dystrophy (GDLD) in a consanguineous Colombian family and determine the underlying genetic cause. METHODS: We performed ocular examination of available family members and bidirectionally Sanger sequenced the GDLD-associated gene, TACSTD2. In one individual, the presence of subepithelial amyloid was confirmed with biopsy. RESULTS: The parents were consanguineous and 5 of their 10 children had GDLD. Typical mulberry subepithelial deposits with subepithelial vascularization were present in 3 individuals; 2 individuals only had mild polymorphic anterior stromal opacity. We identified a homozygous TACSTD2 missense mutation, c.551A>G, p.(Tyr184Cys), in the affected family members. Both parents were heterozygous for the mutation, and unaffected siblings were either heterozygous or homozygous wild-type for this allele. In the Colombian population, this mutation has a minor allele frequency of 0.53%. CONCLUSION: The clinical presentation of GDLD in this family was variable and does not solely support an age-dependent progression of the phenotype, suggesting that environmental or other genetic factors can modify phenotypic expression. The relatively high prevalence of this mutation in the Colombian population suggests that other individuals may have undiagnosed subclinical disease.

Amyloid fibrils containing fragmented ATTR may be the standard fibril composition in ATTR amyloidosis.

Abstract The clinical phenotype of familial ATTR amyloidosis depends to some extent on the particular mutation, but differences exist also within mutations. We have previously described that two types of amyloid fibril compositions exist among Swedish ATTRV30M amyloidosis patients, one consisting of a mixture of intact and fragmented ATTR (type A) and one consisting of mainly intact ATTR (type B). The fibril types are correlated to phenotypic differences. Patients with ATTR fragments have a late onset and develop cardiomyopathy, while patients without fragments have an early onset and less myocardial involvement. The present study aimed to determine whether this correlation between fibril type and phenotype is valid for familial ATTR amyloidosis in general. Cardiac or adipose tissues from 63 patients carrying 29 different TTR non-V30M mutations as well as 13 Japanese ATTRV30M patients were examined. Fibril type was determined by western blotting and compared to the patients' age of onset and degree of cardiomyopathy. All ATTR non-V30M patients had a fibril composition with ATTR fragments, except two ATTRY114C patients. No clear conclusions could be drawn about a phenotype to fibril type correlation among ATTR non-V30M patients. In contrast, Japanese ATTRV30M patients showed a similar correlation as previously described for Swedish ATTRV30M patients. This study shows that a fibril composition with fragmented ATTR is very common in ATTR amyloidosis, and suggests that fibrils composed of only full-length ATTR is an exception found only in a subset of patients.

Relation of clinical, echocardiographic and electrocardiographic features of cardiac amyloidosis to the presence of the transthyretin V122I allele in older African-American men.

Previous studies have shown that 3% to 4% of African Americans carry an amyloidogenic allele of the human serum protein transthyretin (TTR V122I). The allele appears to have an absolute anatomic risk for cardiac amyloid deposition after 65 years of age. In this study, a case-control comparison was performed of clinical, echocardiographic, and electrocardiographic characteristics of 23 age at risk carriers of the amyloidogenic allele and 46 age-, gender-, and ethnically matched noncarriers being evaluated for cardiac disease using standard clinical testing. The 2 groups were matched for blood pressure and the cardiac ejection fraction. None of the subjects had a prestudy diagnosis of cardiac amyloidosis. Carriers of the amyloidogenic allele were found to have statistically significant increases in the occurrence of many of the echocardiographic features of cardiac amyloidosis relative to the noncarriers and a higher frequency of congestive heart failure and atrial fibrillation. The observations suggest that TTR V122I represents a substantial risk for clinically significant cardiac amyloidosis in elderly African American men, behaving as an age-dependent autosomal dominant disease-associated allele. The diagnosis is difficult to make but can be suspected in African Americans aged >60 years on the basis of age, echocardiographic evidence of diastolic dysfunction, and interventricular septal thickening, even in the absence of more recently available sophisticated echocardiographic techniques for evaluating long-axis function and cardiac magnetic resonance imaging. Positive results for the amyloidogenic TTR V122I allele support the diagnosis and define the origin of the disease, which can be confirmed by endomyocardial biopsy.

Clinical and hereditary features of familial vitreous amyloidosis in Chinese.

PURPOSE: To investigate the clinical and hereditary features of a Chinese Han pedigree with familial vitreous amyloidosis. METHODS: The hereditary features of familial traits were detected by drawing genealogy, and the clinical manifestations were observed. RESULTS: This family with 4 generations of 32 family members had the characteristics of euchromosome dominant inheritance. The age of onset in heterozygotes was over 40 years old in male and over 55 in female. All affected individuals had curly hair.Among the 23 family members of the first 3 generations, 7 had the final diagnosis . Four of the cases treated by vitrectomy was found to have open angle glaucoma during the follow-up. CONCLUSION: We reported a Chinese Han pedigree with familial vitreous amyloidosis which is a rare condition in Chinese and described the clinical and hereditary features. The genetic sequencing and animal model are undergoing.

Identification of a novel TTR Gly67Glu mutant and the first case series of familial transthyretin amyloidosis in Hong Kong Chinese.

Familial transthyretin amyloidosis (ATTR), caused by mutant transthyretin deposition, is mainly characterized by peripheral neuropathy, autonomic dysfunction, and cardiomyopathy. There are few reports among the Chinese population. We previously described the TTR mutation (Val30Ala) in the first Hong Kong Chinese family with ATTR. In this study, we report the progress of this family and describe another three unrelated Chinese kinships newly diagnosed with ATTR. The second proband presented mainly with peripheral neuropathy, and genetic analysis of the TTR gene showed alanine-to-serine substitution at amino acid 97. The third proband complained of autonomic dysfunction, and a novel missense mutation of glycine-to-glutamate substitution at amino acid 67 was found. The fourth patient presented with peripheral neuropathy and diastolic cardiomyopathy with the mutation threonine-to-lysine at codon 59. Diagnosis was delayed for more than 2 years. We performed DNA analysis in 46 subjects and detected a total of 21 patients, including the four probands, affected with ATTR, 15 of whom were still at a symptom-free stage at the time of writing. We conclude that ATTR remains largely underdiagnosed in the Chinese population. A high clinical suspicion is crucial for a timely diagnosis and can thus lead to a significant decrease in morbidity and mortality.

Country as the primary risk factor for renal amyloidosis in familial Mediterranean fever.

OBJECTIVE: Familial Mediterranean fever (FMF), the prototype of autoinflammatory disorders, is caused by recessive mutations in the MEFV gene. Some FMF patients develop renal amyloidosis, a potentially fatal condition. This complication has mainly been associated with the M694V mutation, although the different study designs, small numbers of patients, and/or evaluation of few or no covariables calls this association into question. The aim of this study was to examine the controversial issue of amyloidosis susceptibility in FMF by determining the relative contributions of MEFV and numerous epidemiologic factors to the risk of renal amyloidosis. METHODS: Online questionnaires were completed at the MetaFMF database by patients at 35 centers in 14 countries. Using a standardized mode of data collection, we retrieved crude initial data from over half of the genetically confirmed FMF patients referred worldwide until May 2003 (2,482 cases, including 260 patients who developed renal amyloidosis). RESULTS: Amyloid nephropathy was present in 11.4% of the cases. In the total study population, country of recruitment was the leading risk factor for this manifestation (odds ratio 3.2 [95% confidence interval 1.8-5.9]), followed by M694V homozygosity, proband status, and disease duration. Differing results were found when countries were stratified. CONCLUSION: Country of recruitment, rather than MEFV genotype, is the key risk factor for renal amyloidosis in FMF. This risk, which parallels infant mortality rates, indicates a possible environmental origin of amyloidosis susceptibility. The patient's country should be considered in addition to MEFV genotype as an indication for prophylactic colchicine, a treatment suggested for asymptomatic individuals who are incidentally discovered to be M694V homozygous.

[Familial Mediterranean fever in Mexico City. A 20-year follow-up]. / Fiebre mediterránea familiar en la Ciudad de México. Seguimiento durante 20 años.

Familial Mediterranean fever (MFF) is an autosomic recessive, inherited inflammatory disease principally seen in persons from the Mediterranean area. Clinical findings include fever, abdominal pain, and pleuritis. The most severe complication of MFF is renal amyloidosis, manifested as nephrotic syndrome, which evolves into chronic renal failure. In this study, we described clinical findings, evolution, and response to treatment in 52 patients diagnosed with MFF living in Mexico City in whom the most important clinical features were fever and abdominal pain. Differing from previous reported series of patients from the Mediterranean area, patient developed renal amyloidosis during the 20-year follow-up, which suggests that an environmental factor might have a significant influence in development of renal amyloidosis.

Identification of a novel transthyretin Thr59Lys/Arg104His. A case of compound heterozygosity in a Chinese patient diagnosed with familial transthyretin amyloidosis.

Transthyretin (TTR) is a 127-amino acid residue protein synthesized mainly in the liver and in several minor sites, including the choroid plexus and the eye. In plasma, TTR circulates as a homotetramer and transports the hormone thyroxine and the retinol-binding protein-vitamin A complex. It is hypothesized that amino acid substitutions in TTR destabilize the tetramer by causing each subunit toform intermediates that may self-associate into amyloid fibrils. Deposition of wild type TTR, its variants and/or fragments as amyloid fibrils in tissues and organs is associated with familial transthyretin amyloidosis (ATTR). Reported herein is the characterization of a novel TTR Thr59Lys/Arg104His in a patient of Chinese ancestry, who was diagnosed with ATTR. The two variant proteins and the double gene mutations in this compound heterozygous case were detected and identified using a multifaceted approach consisting of isoelectric focusing, electrospray ionization mass spectrometry (MS), matrix-assisted laser desorption/ionization time-of-flight MS in combination with enzymatic digestion, and direct DNA sequence analysis. Previous studies have shown that the TTR Arg104His variant is non-pathologic. It appeared to provide a protective effect in another compound heterozygous case (TTR Val30Met/Arg104His). However, the TTR Arg104His variant when presented with the TTR Thr59Lys variant did not seem to have any protective role.