TNF receptor-associated periodic syndrome (TRAPS): Description of a novel TNFRSF1A mutation and response to etanercept

TRAPS is the most common of the autosomal dominant periodic fever syndromes. It is caused by mutations in the TNFRSF1A gene, which encodes for the type 1 TNF-receptor (TNFR1). We describe here a Brazilian patient with TRAPS associated to a novel TNFRSF1A de novo mutation and the response to anti-TNF therapy. The patient is a 9-year-old girl with recurrent fevers since the age of 3 years, usually lasting 3 to 7 days, and recurring every other week. These episodes are associated with mild abdominal pain, nausea, vomiting and generalized myalgia. Recurrent conjunctivitis and erysipela-like skin lesions in the lower limbs also occur. Laboratory studies show persistent normocytic normochromic anemia, thrombocytosis, elevated erythrocyte sedimentation rate and C-reactive protein. IgD levels are normal. Mutational screening of TNFRSF1A revealed the association of a novel C30F mutation with the common R92Q low-penetrance mutation. The R92Q mutation is seen in 5% of the general population and is associated with an atypical inflammatory phenotype. The patient had a very good response to etanercept, with cessation of fever and normalization of inflammatory markers. Our report expands the spectrum of TNFRSF1A mutations associated with TRAPS, adding further evidence for possible additive effects of a low-penetration R92Q and cysteine residue mutations, and confirms etanercept as an efficacious treatment alternative.

Phenotype-genotype analysis of cryopyrin-associated periodic syndromes (CAPS): Description of a rare non-exon 3 and a novel CIAS1 missense mutation

We describe in this paper the phenotype-genotype analysis of a Brazilian cohort of patients with cryopyrin-associated periodic syndromes (CAPS). Patient 1 presented with an urticarial rash and recurrent fever exacerbated by cold weather, arthritis, and anterior uveitis, thus, receiving a clinical diagnosis of familial cold autoinflammatory syndrome. CIAS1 sequencing identified the T436I mutation, previously associated to a clinical phenotype of chronic infantile neurological cutaneous and articular/neonatal onset multisystem inflammatory disease. Patient 2 developed a papular exanthema with daily fever shortly after birth, frontal bossing, patellae enlargement, and cognitive and motor impairments. Sequencing identified the exceedingly rare G755R CIAS1 mutation in exon 4. Patient 3 developed skin rash and articular symptoms 6 h after birth, followed by aseptic meningitis. He was found to have the novel C148Y missense mutation in CIAS1. This report expands the spectrum of CIAS1 mutations associated to clinical disease, suggests that the same mutation can be associated with different clinical syndromes, and supports the evidence that CAPS patients should always be screened for mutations outside exon 3.

A novel WT1 heterozygous nonsense mutation (p.K248X) causing a mild and slightly progressive nephropathy in a 46,XY patient with Denys-Drash syndrome

WT1 mutations have been described in a variety of syndromes, including Denys-Drash syndrome (DDS), which is characterized by predisposition to Wilms` tumor, genital abnormalities and development of early nephropathy. The most frequent WT1 defects in DDS are missense mutations located in exons 8-9. Our aim is to report a novel WT1 mutation in a 46,XY patient with a DDS variant, who presented a mild nephropathy with a late onset diagnosed during adolescence. He had ambiguous genitalia at birth. At 4 months of age he underwent nephrectomy (Wilms` tumor) followed by chemotherapy. Ambiguous genitalia were corrected and bilateral gonadectomy was performed. Sequencing of WT1 identified a novel heterozygous mutation (c.742A > T) in exon 4 that generates a premature stop codon (p.K248X). Interestingly, this patient has an unusual DDS nephropathy progression, which reinforces that patients carrying WT1 mutations should have the renal function carefully monitored due to the possibility of late-onset nephropathy.

Nonsense Mutations in FGF8 Gene Causing Different Degrees of Human Gonadotropin-Releasing Deficiency

Context: FGFR1 mutations cause isolated hypogonadotropic hypogonadism (IHH) with or without olfactory abnormalities, Kallmann syndrome, and normosmic IHH respectively. Recently, missense mutations in FGF8, a key ligand for fibroblast growth factor receptor (FGFR) 1 in the ontogenesis of GnRH, were identified in IHH patients, thus establishing FGF8 as a novel locus for human GnRH deficiency. Objective: Our objective was to analyze the clinical, hormonal, and molecular findings of two familial IHH patients due to FGF8 gene mutations. Methods and Patients: The entire coding region of the FGF8 gene was amplified and sequenced in two well-phenotyped IHH probands and their relatives. Results: Two unique heterozygous nonsense mutations in FGF8(p.R127X and p.R129X) were identified in two unrelated IHH probands, which were absent in 150 control individuals. These two mutations, mapped to the core domain of FGF8, impact all four human FGF8 isoforms, and lead to the deletion of a large portion of the protein, generating nonfunctional FGF8 ligands. The p.R127X mutation was identified in an 18-yr-old Kallmann syndrome female. Her four affected siblings with normosmic IHH or delayed puberty also carried the p.R127X mutation. Additional developmental anomalies, including cleft lip and palate and neurosensorial deafness, were also present in this family. The p.R129X mutation was identified in a 30-yr-old man with familial normosmic IHH and severe GnRH deficiency. Conclusions: We identified the first nonsense mutations in the FGF8 gene in familial IHH with variable degrees of GnRH deficiency and olfactory phenotypes, confirming that loss-of-function mutations in FGF8 cause human GnRH deficiency. (J Clin Endocrinol Metab 95: 3491-3496, 2010)

A novel STAT5B mutation causing GH insensitivity syndrome associated with hyperprolactinemia and immune dysfunction in two male siblings

Background: GH insensitivity (GHI) syndrome caused by STAT5B mutations was recently reported, and it is characterized by extreme short stature and immune dysfunction. Treatment with recombinant human IGF1 (rhIGF1) is approved for patients with GHI, but the growth response to this therapy in patients with STAT5B mutations has not been reported. Objectives: To report the clinical features, molecular findings, and the short-term growth response to rhIGF1 therapy in patients with STAT5B mutation. Subjects and methods: Hormonal and immunological evaluations were performed in two male siblings with GHI associated with atopic eczema, interstitial lung disease, and thrombocytopenic purpura. STAT5B genes were directly sequenced. The younger sibling was treated with rhIGF1 at a dose of 110 mu g/kg BID. Results: Both siblings had laboratory findings compatible with GHI associated with hyperprolactinemia. Lymphopenia and reduced number of natural killer cells without immunoglobulin abnormalities were observed. STAT5B sequence revealed a homozygous frameshift mutation (p.L142fsX161) in both siblings. The younger sibling (9.9 years of age) was treated with rhIGF1 at appropriate dosage, and he did not present any significant change in his growth velocity (from 2.3 to 3.0 cm/year after 1.5 years of therapy). The presence of a chronic illness could possibly be responsible for the poor result of rhIGF1 treatment. Further studies in patients with STAT5B defects are necessary to define the response to rhIGF1 treatment in this disorder. Conclusion: GHI associated with immune dysfunction, especially interstitial lung disease, and hyperprolactinemia is strongly suggestive of a mutation in STAT5B in both sexes.

A novel homozygous splice acceptor site mutation of KISS1R in two siblings with normosmic isolated hypogonadotropic hypogonadism

Context: Loss-of-function mutations of the kisspeptin-1 receptor gene, KISS1R, have been identified in patients with normosmic isolated hypogonadotropic hypogonadism (nIHH). Objective: To investigate KISS1R defects in patients with absent or delayed puberty. Patients: We investigated KISS1R gene defects in a cohort of 99 Brazilian patients with nIHH or constitutional delay of puberty (CDP). Methods: The entire coding region of KISS1R was amplified by PCR followed by automatic sequencing. In addition, screening for KISS1R exonic deletions was performed by multiplex ligation-dependent probe amplification. Results: One novel homozygous KISS1R mutation was identified in two siblings with nIHH. This variant was an insertion/deletion (indel) mutation characterized by the deletion of three nucleotides (GCA) at position -2 to -4, and by the insertion of seven nucleotides (ACCGGCT) at the same position, within the 30 splice acceptor site of intron 2 of KISS1R. The brothers who carried this KISS1R mutation had no clinical evidence of pubertal development at the ages of 14 and 20 years. Computational analysis of this indel mutation predicted the generation of an abnormal protein. In addition, a new heterozygous KISS1R variant (p.E252Q) was identified in a male patient with sporadic nIHH. However, in vitro studies of this variant did not demonstrate functional impairment. Only known polymorphisms were identified in patients with CDP. Conclusion: Loss-of-function mutations of KISS1R represents a rare cause of nIHH, and was absent in patients with CDP. We have described a novel KISS1R homozygous splice acceptor site mutation in the familial form of nIHH.

Multi-system neurological disease is common in patients with OPA1 mutations

Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal `dominant optic atrophy plus` variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44-6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08-4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment.

Pompe disease in a Brazilian series: clinical and molecular analyses with identification of nine new mutations

Pompe disease (glycogen storage disease type II or acid maltase deficiency) is an inherited autosomal recessive deficiency of acid alpha-glucosidase (GAA), with predominant manifestations of skeletal muscle weakness. A broad range of studies have been published focusing on Pompe patients from different countries, but none from Brazil. We investigated 41 patients with either infantile-onset (21 cases) or late-onset (20 cases) disease by muscle pathology, enzyme activity and GAA gene mutation screening. Molecular analyses identified 71 mutant alleles from the probands, nine of which are novel (five missense mutations c.136T > G, c.650C > T, c.1456G > C, c.1834C > T, and c.1905C > A, a splice-site mutation c.1195-2A > G, two deletions c.18_25del and c.2185delC, and one nonsense mutation c.643G > T). Interestingly, the c.1905C > A variant was detected in four unrelated patients and may represent a common Brazilian Pompe mutation. The c.2560C > T severe mutation was frequent in our population suggesting a high prevalence in Brazil. Also, eight out of the 21 infantile-onset patients have two truncating mutations predicted to abrogate protein expression. Of the ten late-onset patients who do not carry the common late-onset intronic mutation c.-32-13T > G, five (from three separate families) carry the recently described intronic mutation, c.-32-3C > A, and one sibpair carries the novel missense mutation c.1781G > C in combination with known severe mutation c.1941C > G. The association of these variants (c.1781G > C and c.-32-3C > A) with late-onset disease suggests that they allow for some residual activity in these patients. Our findings help to characterize Pompe disease in Brazil and support the need for additional studies to define the wide clinical and pathological spectrum observed in this disease.

Linkage of Paget disease of bone to a novel region on human chromosome 18q23

Paget disease of bone (PDB) is characterized by increased osteoclast activity and localized abnormal bone remodeling. PDB has a significant genetic component, with evidence of linkage to chromosomes 6p21.3 (PDB1) and 18q21-22 (PDB2) in some pedigrees. There is evidence of genetic heterogeneity, with other pedigrees showing negative linkage to these regions. TNFRSF11A, a gene that is essential for osteoclast formation and that encodes receptor activator of nuclear factor-kappa B (RANK), has been mapped to the PDB2 region. TNFRSF11A mutations that segregate in pedigrees with either familial expansile osteolysis or familial PDB have been identified; however, linkage studies and mutation screening have excluded the involvement of RANK in the majority of patients with PDB. We have excluded linkage, both to PDB1 and to PDB2, in a large multigenerational pedigree with multiple family members affected by PDB. We have conducted a genomewide scan of this pedigree, followed by fine mapping and multipoint analysis in regions of interest. The peak two-point LOD scores from the genomewide scan were 2.75, at D7S507, and 1.76, at D18S70. Multipoint and haplotype analysis of markers flanking D7S507 did not support linkage to this region. Haplotype analysis of markers flanking D18S70 demonstrated a haplotype segregating with PDB in a large subpedigree. This subpedigree had a significantly lower age at diagnosis than the rest of the pedigree (51.2 +/- 8.5 vs. 64.2 +/- 9.7 years; P = .0012). Linkage analysis of this subpedigree demonstrated a peak two-point LOD score of 4.23, at marker D18S1390 (theta = 0), and a peak multipoint LOD score of 4.71, at marker D18S70. Our data are consistent with genetic heterogeneity within the pedigree and indicate that 18q23 harbors a novel susceptibility gene for PDB.

Germline BRCA1 promoter deletions in UK and Australian familial breast cancer patients: Identification of a novel deletion consistent with BRCA1 :psi VBRCA1 recombination

Inherited susceptibility to breast cancer results from germline mutations in one of a number of genes including BRCA1. A significant number of BRCA1-linked familial breast cancer patients, however, have no detectable BRCA1 mutation. This could be due in part to the inability of commonly used mutation-detection techniques to identify mutations outside the BRCA1 coding region. This paper addresses the hypothesis that non coding region mutations, specifically in the BRCA1 promoter, account for some of these cases. We describe a new and detailed restriction map of the 5' region of the BRCA1 gene including the nearby NBR2, psiBRCA1, and NBR1 genes and the isolation of a number of new informative hybridization probes suitable for Southern analysis. Using this information we screened DNA from lymphoblastoid cell-lines made from 114 UK familial breast cancer patients and detected one large deletion in the 5' region of BRCA1. We show that the breakpoints for this deletion are in BRCA1 intron 2 and between NBR2 and exon 2 of psiBRCA1, raising the possibility that this deletion arose via a novel mechanism involving BRCA1:psiBRCA1 recombination. We have also screened 60 familial breast cancer patients from the Australian population, using an amplification refractory mutation system (ARMS) technique described previously by our group, and found one patient with a genotype consistent with a BRCA1 promoter deletion. These findings indicate that germline BRCA1 promoter deletions are a rare and yet significant mutation event and that they could arise via a novel genetic mechanism. Hum Mutat 19:435-442, 2002. (C) 2002 Wiley-Liss, Inc.

Localization of a novel melanoma susceptibility locus to 1p22

Over the past 20 years, the incidence of cutaneous malignant melanoma (CMM) has increased dramatically worldwide. A positive family history of the disease is among the most established risk factors for CMM; it is estimated that 10% of CMM cases result from an inherited predisposition. Although mutations in two genes, CDKN2A and CDK4, have been shown to confer an increased risk of CMM, they account for only 20%-25% of families with multiple cases of CMM. Therefore, to localize additional loci involved in melanoma susceptibility, we have performed a genomewide scan for linkage in 49 Australian pedigrees containing at least three CMM cases, in which CDKN2A and CDK4 involvement has been excluded. The highest two-point parametric LOD score (1.82; recombination fraction [theta] 0.2) was obtained at D1S2726, which maps to the short arm of chromosome 1 (1p22). A parametric LOD score of 4.65 (theta = 0) and a nonparametric LOD score of 4.19 were found at D1S2779 in nine families selected for early age at onset. Additional typing yielded seven adjacent markers with LOD scores 13 in this subset, with the highest parametric LOD score, 4.95 (theta = 0) ( nonparametric LOD score 5.37), at D1S2776. Analysis of 33 additional multiplex families with CMM from several continents provided further evidence for linkage to the 1p22 region, again strongest in families with the earliest mean age at diagnosis. A nonparametric ordered sequential analysis was used, based on the average age at diagnosis in each family. The highest LOD score, 6.43, was obtained at D1S2779 and occurred when the 15 families with the earliest ages at onset were included. These data provide significant evidence of a novel susceptibility gene for CMM located within chromosome band 1p22.

Mutations du roman français depuis les années quatre-vingt : le parcours de Jean Echenoz

Artigo também disponível no PROA-UA: plataforma de revistas em open access da universidade de aveiro com o URI http://revistas.ua.pt/index.php/Carnets/article/view/808/742.

The Spectrum of Mutations and Molecular Pathogenesis of Hemophilia A in 181 Portuguese Patients

Disease-causing alterations within the F8 gene were identified in 177 hemophilia A families of Portuguese origin. The spectrum of non-inversion F8 mutations in 101 families included 67 different alterations, namely: 36 missense, 8 nonsense and 4 splice site mutations, as well as 19 insertions/deletions. Thirty-four of these mutations are novel. Molecular modeling allowed prediction of the conformational changes introduced by selected amino acid substitutions and their correlation with the patients' phenotypes. The relatively frequent, population-specific, missense mutations together with de novo alterations can lead to significant differences in the spectrum of F8 mutations among different populations.

A Novel Autosomal Recessive GJA1 Missense Mutation Linked to Craniometaphyseal Dysplasia

Craniometaphyseal dysplasia (CMD) is a rare sclerosing skeletal disorder with progressive hyperostosis of craniofacial bones. CMD can be inherited in an autosomal dominant (AD) trait or occur after de novo mutations in the pyrophosphate transporter ANKH. Although the autosomal recessive (AR)form of CMD had been mapped to 6q21-22 the mutation has been elusive. In this study, we performed whole-exome sequencing for one subject with AR CMD and identified a novel missense mutation (c.716G>A, p.Arg239Gln) in the C-terminus of the gap junction protein alpha-1 (GJA1) coding for connexin 43 (Cx43). We confirmed this mutation in 6 individuals from 3 additional families. The homozygous mutation cosegregated only with affected family members. Connexin 43 is a major component of gap junctions in osteoblasts, osteocytes, osteoclasts and chondrocytes. Gap junctions are responsible for the diffusion of low molecular weight molecules between cells. Mutations in Cx43 cause several dominant and recessive disorders involving developmental abnormalities of bone such as dominant and recessive oculodentodigital dysplasia (ODDD; MIM #164200, 257850) and isolated syndactyly type III (MIM #186100), the characteristic digital anomaly in ODDD. However, characteristic ocular and dental features of ODDD as well as syndactyly are absent in patients with the recessive Arg239Gln Cx43 mutation. Bone remodeling mechanisms disrupted by this novel Cx43 mutation remain to be elucidated.

Aging and Alzheimer's disease: Searching for novel molecular cues

Tese de Doutoramento em Ciências da Saúde