Mutations in the gene encoding mevalonate kinase cause hyper-IgD and periodic fever syndrome. International Hyper-IgD Study Group.

Hyperimmunoglobulinaemia D and periodic fever syndrome (HIDS; MIM 260920) is a rare, apparently monogenic, autosomal recessive disorder characterized by recurrent episodes of fever accompanied with lymphadenopathy, abdominal distress, joint involvement and skin lesions. All patients have high serum IgD values (>100 U/ml) and HIDS 'attacks' are associated with an intense acute phase reaction whose exact pathophysiology remains obscure. Two other hereditary febrile disorders have been described. Familial Mediterranean fever (MIM 249100) is an autosomal recessive disorder affecting mostly populations from the Mediterranean basin and is caused by mutations in the gene MEFV (refs 5,6). Familial Hibernian fever (MIM 142680), also known as autosomal dominant familial recurrent fever, is caused by missense mutations in the gene encoding type I tumour necrosis factor receptor. Here we perform a genome-wide search to map the HIDS gene. Haplotype analysis placed the gene at 12q24 between D12S330 and D12S79. We identified the gene MVK, encoding mevalonate kinase (MK, ATP:mevalonate 5-phosphotransferase; EC 2.7.1.36), as a candidate gene. We characterized 3 missense mutations, a 92-bp loss stemming from a deletion or from exon skipping, and the absence of expression of one allele. Functional analysis demonstrated diminished MK activity in fibroblasts from HIDS patients. Our data establish MVK as the gene responsible for HIDS.

Mutations in the autoinflammatory cryopyrin-associated periodic syndrome gene: epidemiological study and lessons from eight years of genetic analysis in France.

BACKGROUND: Cryopyrin-associated periodic syndromes (CAPS) consist of a continuum of autoinflammatory diseases caused by a defect in interleukin 1ß regulation. Although symptoms may vary widely, the discovery, in 2001, of the gene involved (NLRP3) has dramatically helped diagnosis. OBJECTIVES: To define the spectrum and prevalence of NLRP3 mutations in France and to delineate initial criteria before molecular analysis. METHODS: Retrospective review (2001-9) of genetic analysis data and request forms of patients living in France with an NLRP3 mutation since the set up of CAPS molecular diagnosis by the three French laboratories providing this test (GenMAI network). RESULTS: Over 800 analyses of this gene have been conducted, identifying 135 cases with an NLRP3 mutation (55 probands; 33 multiplex families); the estimated prevalence in France was equal to 1/360 000. A total of 21 different sequence variants were detected, among which four are common and nine are new mutations. CONCLUSIONS: Although the number of NLRP3 test requests has doubled over the past 5 years, genetic screening has not contributed to enhanced detection of new index cases each year. There are two possible reasons for this: (i) no clinical prerequisite for genetic diagnosis and (ii) few new large families are now identified (unlike the initial study based on a selection by linkage). A set of initial clinical criteria have been drawn up which it is recommended should be fulfilled before a patient is tested: at least three recurrent bouts, age at disease onset < 20 years and elevated levels of C-reactive protein, especially in individuals with urticaria and moderate fever.

Genetically determined recurrent fevers.

The usefulness of molecular diagnosis is now well established for genetically determined recurrent fevers. In familial Mediterranean fever, the severity of the disease and the risk of renal amyloidosis are correlated with mutations in MEFV, and the serum amyloid-associated protein (SAA)1 alpha/alpha allele is a modifying factor for amyloidosis. Study of the genes in various species shows that the human mutations represent a reappearance of the ancestral amino acid state and the B30-2 domain, where most human mutations are localized, is absent in the rat and mouse proteins. Since the discovery of the responsible gene, TNF-receptor-associated periodic syndrome seems to be more frequent than previously considered. Among the new mutations described, some are associated with an incomplete penetrance.

Molecular analysis of MVK mutations and enzymatic activity in hyper-IgD and periodic fever syndrome.

Hyperimmunoglobulinaemia D and periodic fever syndrome (HIDS) is an autosomal recessive inflammatory disorder characterised by recurrent episode of fever associated with lymphadenopathy, abdominal distress, joint involvement and skin lesions. We recently demonstrated that mutations in the mevalonate kinase gene (MVK) are associated with HIDS. Direct DNA sequencing was done to screen the entire coding region of MVK in 25 unrelated patients with HIDS. Mutations were detected in the coding region of the gene including 11 missense mutations, one deletion, the absence of expression of one allele, as well as three novel polymorphisms. Seven of these mutations are novel. The large majority of the patients were compound heterozygotes for two mutations. Of these, V377I (G-->A) is the most common mutation occurring in 20 unrelated patients and was found to be associated with I268T in six patients. Mutations were associated with a decrease of mevalonate kinase (MK) (ATP:mevalonate 5-phosphotransferase, EC 2.7.I.36) enzymatic activity but not as profound as in mevalonic aciduria, a syndrome also caused by a deficient activity of MK. In HIDS the mutations are located all along the protein which is different from mevalonic aciduria where MK mutations are mainly clustered to a same region of the protein. On the basis of this study, we propose that the diagnostic screen of MVK in HIDS should be first directed on V377I and I268T mutations. Three patients are also described to illustrate the genotypic and phenotypic overlap with mevalonic aciduria.

Familial Mediterranean fever in Lebanon: mutation spectrum, evidence for cases in Maronites, Greek orthodoxes, Greek catholics, Syriacs and Chiites and for an association between amyloidosis and M694V and M694I mutations.

Seventy-nine unrelated Lebanese patients were tested for 15 mutations in the MEFV gene: A761H, A744S, V726A, K695R, M694V, M694I, M694del, M6801 (G --> C), M680I (G --> A) in exon 10, F479L in exon 5, P369S in exon 3, T267I, E167D and E148Q in exon 2, using PCR digestion, ARMS, DGGE and/or sequencing. Mutations were detected in patients belonging to all communities, most interestingly the Maronite, Greek orthodox, Greek catholic, Syriac and Chiite communities. The most frequent mutations are M694V and V726A (27% and 20% of the total alleles respectively). M694I, E148Q and M680I mutations account respectively for 9%, 8% and 5%. Each of the K695R, E167D and F479L mutations was observed once and all the remaining mutations were not encountered. Of the alleles 33% do not carry any of the studied mutations. The mutation spectra, clinical features and severity of the disease differed among the Lebanese communities. The genotype-phenotype analysis showed a significant association (P < 0.001) between amyloidosis and the presence of mutations at codon 694 in exon 10 (both M694V and M694I). None of the patients carrying other mutations developed amyloidosis.

The 25 kDa protein kinase inhibitor present in liver cell is absent in fast growing HTC cells and is induced in sodium butyrate treated cells.

We have recently characterized a cAMP independent protein kinase inhibitor in rat liver. This inhibitor is absent or inactive in fast growing HTC cells and is induced according to exponential kinetics by sodium butyrate, a compound which arrests cell growth at the G1 phase of the cell cycle. It is suggested that the inhibitor could be involved in cell growth regulation.

Recurrent subarachnoid hemorrhage associated with a new transthyretin variant (Gly53Glu).

CNS involvement is rare in systemic amyloidoses due to transthyretin (TTR) mutation and manifests as a combination of dementia, seizures, and myelopathy. The authors report two French siblings who experienced recurrent subarachnoid hemorrhages as the main clinical feature. Brain specimens showed that the leptomeningeal vessels walls were thickened by amyloid deposits, and sequencing of the TTR exons showed a heterozygous single base-pair transition from G to A (codon 53), resulting in a glycine for glutamic acid substitution (G53E).

In vitro, non enzymatic labelling of histone H1 with [14C] acetyl CoA.

Histones H 1A and H 1B, in nuclear homogenates or after purification, are able to be acetylated or labelled by [14C] acetyl CoA in the absence of enzyme, as shown after blotting into nitrocellulose sheets. The reaction is pH-dependent, resistant to 2 M NaCl and does not occur at high ionic strength.

The protein kinases tightly bound to DNA are present in normal tissues and in regenerating liver, but strongly decreased in hepatomas.

We have previously described in rat liver two protein kinases tightly bound to DNA, one is serine-specific, the other arginine-specific. In this work we show that both enzymes are present in various rat tissues and in liver from various species. Both kinase specific activities are strongly decreased in methyl-DBA-induced hepatomas and in HTC cells but not in regenerating liver after hepatectomy. This decrease is then not related to cell proliferation.

Purification and comparison of liver microsomal flavin-containing monooxygenase from normal and streptozotocin-diabetic rats.

Liver microsomal flavin-containing monooxygenase (FMO) activity towards thiobenzamide is two-fold increased in streptozotocin diabetic (insulin deficient) rats and mice and, to a lesser degree in congenital insulin resistant Ob/Ob mice. No difference in thermal stability appears between microsomal FMOs from both normal and diabetic rats. FMO has been purified to homogeneity from these two sources, with a 50-fold increase of specific activity. Their apparent molecular weight is respectively 50,000 and 49,000 and a discrete modification appears in the HPLC profiles of tryptic peptides from purified FMOs. They appear immunochemically very similar and present in equal quantity in microsomal membranes from both normal and diabetic rats, so that the increased activity cannot be ascribed to an increased concentration of the enzyme protein.

Mutations in the MEFV gene in a large series of patients with a clinical diagnosis of familial Mediterranean fever.

Familial Mediterranean fever (FMF) is an autosomal recessively inherited disease affecting patients of the Mediterranean basin. FMF is characterized by recurrent episodes of fever accompanied with topical signs of inflammation. Some patients can develop a renal amyloidosis associated (AA) amyloidosis. The administration of colchicine is an effective preventive treatment of both the attacks and amyloidosis. The FMF gene (MEFV) was cloned and missense mutations were found to be responsible for the disease. We investigated a large series of 303 unselected and unrelated patients of various ethnic backgrounds with a clinical suspicion of FMF to confirm or invalidate the diagnosis of FMF and to determine the spectrum of MEFV mutations. Molecular analysis focused on all the most frequent mutations identified so far, and an exhaustive analysis of exon 10, containing the mutational hotspot, was performed through DNA sequencing. Sixty-two percent of Sephardic, North African Arabs, Armenian and Turkish patients were either homozygous or compound heterozygous for MEFV mutations. In other populations surrounding the Mediterranean Sea such as Greek, Italian, Portuguese, Kurdish and Lebanese populations, mutations were also found. In general, patients without Mediterranean origin had no mutations in the MEFV gene. Two new mis-sense mutations were identified in exon 10 of the MEFV gene: the S675N in an Italian patient and the M680L in a French patient without any known at-risk ethnic ancestry.

A novel variant of granular corneal dystrophy caused by association of 2 mutations in the TGFBI gene-R124L and DeltaT125-DeltaE126.

OBJECTIVE: To characterize the molecular defect in the TGFBI gene in a French family affected with an atypical granular corneal dystrophy. PATIENTS: This family comprises 9 affected individuals across 3 generations without consanguineous marriage. METHODS: Light and electron microscopy were used to examine corneal buttons from patients. Exons of the TGFBI gene were amplified by polymerase chain reaction and sequenced directly using an automated method. Restriction digestion analysis and heteroduplex screening were performed to confirm that the mutations identified were not polymorphisms. RESULTS: Round or snow-flakes-like deposits that stained red with Masson trichrome and appeared as dense, rod-shaped structures were observed in the most anterior layers of the central stroma. All patients were heterozygous for the R124L mutation and a novel mutation predicting the deletion of 2 amino acid residues-threonine (T) and glutamic acid (E)-at codons 125 and 126. CONCLUSIONS: This French family is affected with a novel variant of granular dystrophy that is caused by a molecular defect in the TGFBI gene, reported here for the first time. CLINICAL RELEVANCE: These 2 mutations cause a novel variant of granular dystrophy that is intermediate in severity between the classical and superficial variant forms. Arch Ophthalmol. 2000;118:814-818

A novel variant of transthyretin (Glu42Asp) associated with sporadic late-onset cardiac amyloidosis.

A sixty-three year old French man presented with isolated late-onset amyloid cardiomyopathy proven by endomyocardial biopsy. There was no known family history of amyloidosis. Immunohistochemistry of cardiac deposits suggested that amyloi fibrils were derived from transthyretin. DNA sequencing revealed a point mutation in exon 2 of the transthyretin gene responsible for a novel amyloidogenic variant Asp42.

Fibrinogen A alpha chain mutation (Arg554 Leu) associated with hereditary renal amyloidosis in a French family.

A French family with hereditary renal amyloidosis (HRA) was studied. The disease presented in 7 of the 8 affected individuals with proteinuria or the nephrotic syndrome. The age of onset was in the fifth decade of life. There is currently no sign of extrarenal involvement in any affected individual. However, the nephropathy in this family is progressive and led to terminal renal failure in 4 patients. Immunohistochemistry studies of glomerular amyloid deposits suggested that the amyloid protein was the fibrinogen A alpha chain. Direct DNA sequencing revealed a G 4993 T transversion and subsequently Arg 554 Leu mutation in the fibrinogen A alpha chain. This is the first description of this fibrinogen A alpha chain mutation in Europe. This family is of French descent and cannot be related to the previously reported Peruvian/Mexican and African-American kindreds.

Clinical versus genetic diagnosis of familial Mediterranean fever.

The diagnosis of familial Mediterranean fever (FMF) has until recently been based on clinical signs alone. Discovery of the MEFV gene has enabled a molecular approach to diagnosis, which is already well established for diagnosing typical clinical forms of FMF. We evaluated the utility of this molecular approach in a large series of patients with various clinical presentations and ethnic origins. We looked for mutations in the MEFV gene in 303 unselected consecutive patients with a variable (from high to low) clinical suspicion of FMF. Two mutations were found in 133 patients (44%). In 22 patients (7%), the clinical diagnosis of FMF was unlikely according to the Tel Hashomer clinical criteria. Our results suggest that the spectrum of FMF-associated signs is broader than previously believed. Wider indications for genotyping should lead to more frequent diagnosis of FMF.

Dual intracellular signaling pathways mediated by the human cannabinoid CB1 receptor.

It has long been established that the cannabinoid CB1 receptor transduces signals through a pertussis toxin-sensitive Gi/Go inhibitory pathway. Although there have been reports that the cannabinoid CB1 receptor can also mediate an increase in cyclic AMP levels, in most cases the presence of an adenylyl cyclase costimulant or the use of very high amounts of agonist was necessary. Here, we present evidence for dual coupling of the cannabinoid CB receptor to the classical pathway and to a pertussis toxin-insensitive adenylyl cyclase stimulatory pathway initiated with low quantities of agonist in the absence of any costimulant. Treatment of Chinese hamster ovary (CHO) cells expressing the cannabinoid CB1 receptor with the cannabinoid CP 55,940, {(-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hyd roxypropyl) cyclohexan-1-ol} resulted in cyclic AMP accumulation in a dose-response manner, an accumulation blocked by the cannabinoid CB1 receptor-specific antagonist SR 141716A, {N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-me thyl-1H-pyrazole-3-carboxamide hydrochloride}. In CHO cells coexpressing the cannabinoid CB1 receptor and a cyclic AMP response element (CRE)-luciferase reporter gene system, CP 55,940 induced luciferase expression by a pathway blocked by the protein kinase A inhibitor N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide hydrochloride (H-89). Under the same conditions the peripheral cannabinoid CB2 receptor proved to be incapable of inducing cAMP accumulation or luciferase activity. This incapacity allowed us to study the luciferase activation mediated by CB /CB2 chimeric constructs, from which we determined that the first and second internal loop regions of the cannabinoid CB1 receptor were involved in transducing the pathway leading to luciferase gene expression.

A new mutation (A546T) of the betaig-h3 gene responsible for a French lattice corneal dystrophy type IIIA.

PURPOSE: To characterize the betaig-h3 gene defect in a French family affected with lattice corneal dystrophy type IIIA (LCDIIIA). METHODS: Histologic examination was performed from corneal buttons of two patients. Genomic DNA was extracted from leukocytes, and exons of the betaig-h3 gene were amplified by polymerase chain reaction to be directly sequenced. RESULTS: Numerous deposits were evident in the stroma and beneath the Bowman membrane, which had all the features of amyloid deposits. Analysis of exon 12 revealed a heterozygous G to A transition on codon 546. CONCLUSION: In contrast to Japanese patients, these French patients affected with LCDIIIA carry a distinct mutation of the betaig-h3 gene (A546T instead of P501T). Therefore, it is unclear whether different mutations could result in the same dystrophy or whether we are dealing with clinical heterogeneity of LCDIIIA.

Study of C4A mRNA in mononuclear blood cells from a patient with SLE and C4A homozygous deficiency without C4A gene deletion.

C4A null alleles (C4AQ0) have an increased frequency in SLE patients. Surprisingly some of them have no detectable gene deletion. In order to characterize the level of the defect in such patients, we used a RT-PCR/nested PCR technique and detected the presence of C4A mRNA in normal amounts. Since maturation abnormalities are almost always accompanied by a decrease in mRNA concentration, this result suggests that the defect may be located at the translational level.

[Molecular genotyping: development and limits]. / Génotypage moléculaire: développement et limites.

Kits dedicated to molecular genotyping are now commercially available and are routinely used for diagnosis purpose. In the future these kits that use the classical reverse dot-blot approach will be replaced by micro-arrays, DNA chips and Labs on a chip. Some systems and DNA chips designed for medical diagnosis are already available. The present main problem is their very high cost.

[Genetic testing]. / Les tests génétiques.

The first genetic tests started to be developed about twenty years ago. Their initial applications were limited to genetic counselling and prenatal diagnosis of a few hereditary diseases. Technological progress and the identification of genes responsible for many hereditary diseases have led to their development and diffusion. They have become a nearly irreplaceable tool for the diagnosis of hereditary diseases. In the future, their indications should increase when genes implicated in multifactorial diseases are progressively identified. The impact will probably be particularly important in cardiology because most cardiovascular diseases are multifactorial. The first predisposing factors (factor V. prothrombin...) for a predisposition to thrombosis are now daily genetic investigations. In parallel, the progress in pharmacogenetics should enable everyone to have appropriate qualitative and quantitative treatment according to their genetic makeups, which should improve both efficacy and safety. In order to face up to the exponential increase in demand for the genetic tests which will result from these advances, the laboratories should have new high speed, powerful and economic equipment. DNA microchips, which are currently under development could, at least initially, provide a solution to this problem. It is now certain that genetic testing will become routine and, in time, it will be used massively in both hospital and community medicine.