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PubMed2004

Anterior basement membrane corneal dystrophy and pseudo-unilateral lattice corneal dystrophy in a patient with recurrent corneal erosions.

PURPOSE: To report the utility of genetic testing in the diagnosis and management of patients with suspected corneal dystrophies. DESIGN: Case report. METHODS: A 58-year-old man with a history of recurrent corneal erosions was diagnosed with bilateral anterior basement membrane dystrophy and unilateral lattice corneal dystrophy. All 17 exons of the TGFBI gene were screened for mutations previously associated with lattice corneal dystrophy as well as novel coding region changes. RESULTS: No mutations were found in the 17 exons of the TGFBI gene. A nucleotide change in exon 6 (651C>G) did not result in a change in the encoded amino acid (Leu217Leu). CONCLUSIONS: In cases of suspected TGFBI corneal dystrophies, genetic testing is a useful tool to confirm the clinical diagnosis. In this case of suspected unilateral lattice corneal dystrophy, screening of the TGFBI gene ruled out the diagnosis, raising the possibility that the corneal changes were related to the coexistent anterior basement membrane dystrophy.

Basement Membrane↗
PubMed2006

Recurrence of proteinuria 10 years post-transplant in NPHS2-associated focal segmental glomerulosclerosis after conversion from cyclosporin A to sirolimus.

Mutations in the NPHS2 gene, which encodes podocin, are associated with steroid-resistant nephrotic syndrome in childhood. Renal histology frequently presents focal segmental glomerulosclerosis (FSGS). Post-transplant recurrence of proteinuria in patients affected by homozygous or compound heterozygous NPHS2 mutation is encountered rarely (1-2%) compared to 30% recurrence in nonhereditary FSGS. We report on a pediatric kidney transplant recipient with NPHS2-associated nephrotic syndrome and FSGS, who developed biopsy-proven recurrence of FSGS 10 years post-transplant in temporal association with conversion from cyclosporin A (CsA)- to sirolimus (SRL)-based immunosuppression, due to histological evidence of severe CsA-induced nephrotoxicity. Reswitch of the immunosuppressive regimen from SRL to CsA led to a noticeable decrease of proteinuria and to stabilization of graft function. We conclude that patients with hereditary FSGS are not entirely protected from post-transplant recurrence of proteinuria, even in the long term. The close temporal relationship of FSGS recurrence with CsA withdrawal and conversion to SRL suggests that caution should be exercised in the use of CsA-free immunosuppression also in patients with NPHS2-associated FSGS.

Adolescent↗
PubMed1997

Three germline mutations in the TP53 gene.

Three germline mutations in the TP53 tumor-suppressor gene are reported, two of which are not reported previously. A missense mutation at codon 265 of TP53 was found in three patients of a family that complied with the definition of the Li-Fraumeni syndrome. A nonsense mutation in codon 306 was found in a woman who had had a rhabdomyosarcoma at age 4 and a subsequent breast cancer at age 22. She was part of a Li-Fraumeni-like family, but the parental origin of the mutation could not be traced. Finally, while screening for somatic alterations in TP53 in a series of 141 sporadic breast tumors, we detected a constitutional missense mutation in codon 235 in a woman diagnosed with breast cancer at age 26 and a recurrence 4 years later. The recurrence, but not the primary tumor, showed an additional missense mutation at codon 245 as well as loss of the wild-type allele. This suggests that the 245 mutation was particularly important for tumor progression and that there might exist heterogeneity in terms of cancer predisposition potential among the various germline TP53 mutations.

Breast Neoplasms↗
PubMed2003

c-kit gene mutation at exon 17 or 13 is very rare in sporadic gastrointestinal stromal tumors.

BACKGROUND AND AIM: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the human gut. They frequently have gain-of-function mutations of the c-kit gene, which encodes a receptor, tyrosine kinase. The mutations were found at exon 11 in most cases, and either at exon 9 or at exon 13 in rare cases. Recently, we found a family with multiple GIST and a gain-of-function mutation at exon 17. The family was the first reported GIST case with c-kit gene mutation at exon 17 including sporadic GIST. Although we previously reported that the c-kit gene mutation at exon 17 was not detected in 124 sporadic GIST by single-strand conformation polymorphism (SSCP) analysis, the mutation at exon 17 observed in the familial GIST was detectable by the use of direct sequencing but not by our SSCP method. In the present study, we examined the mutations at exon 17 and exon 13 by using direct sequencing. METHODS: Genomic DNA was extracted from formalin-fixed, paraffin-embedded GIST tissues. We could obtain 143 sporadic GIST cases appropriate for DNA analysis at exon 17 and 141 at exon 13. Exons 17 and 13 were amplified by using polymerase chain reaction and direct sequencing was conducted. RESULTS: No mutation was found at exon 17, and only one case with the mutation at exon 13 was observed. The GIST with the mutation at exon 13 was large and showed frequent mitosis, and the patient died of the recurrent GIST 3 years after the first operation. CONCLUSION: The mutation at exons 17 or 13 was considered to be very rare in sporadic GIST.

Aged↗
PubMed2005

KIT-D816 mutations in AML1-ETO-positive AML are associated with impaired event-free and overall survival.

Mutations in codon D816 of the KIT gene represent a recurrent genetic alteration in acute myeloid leukemia (AML). To clarify the biologic implication of activation loop mutations of the KIT gene, 1940 randomly selected AML patients were analyzed. In total, 33 (1.7%) of 1940 patients were positive for D816 mutations. Of these 33 patients, 8 (24.2%) had a t(8;21), which was significantly higher compared with the subgroup without D816 mutations. Analyses of genetic subgroups showed that KIT-D816 mutations were associated with t(8;21)/AML1-ETO and other rare AML1 translocations. In contrast, other activating mutations like FLT3 and NRAS mutations were very rarely detected in AML1-rearranged leukemia. KIT mutations had an independent negative impact on overall (median 304 vs 1836 days; P = .006) and event-free survival (median 244 vs 744 days; P = .003) in patients with t(8;21) but not in patients with a normal karyotype. The KIT-D816V receptor expressed in Ba/F3 cells was resistant to growth inhibition by the selective PTK inhibitors imatinib and SU5614 but fully sensitive to PKC412. Our findings clearly indicate that activating mutations of receptor tyrosine kinases are associated with distinct genetic subtypes in AML. The KIT-D816 mutations confer a poor prognosis to AML1-ETO-positive AML and should therefore be included in the diagnostic workup. Patients with KIT-D816-positive/AML1-ETO-positive AML might benefit from early intensification of treatment or combination of conventional chemotherapy with KIT PTK inhibitors.

Adult↗
PubMed2006

Goats, germs, and fever: Are the pyrin mutations responsible for familial Mediterranean fever protective against Brucellosis?

Mutations in the MEFV gene are highly prevalent in the Middle East and Mediterranean basin, with carrier rates of up to 1:3 in some populations. More than 50 mutations in the MEFV gene have been described. The high prevalence, multiple mutations, and geographic localization to the Middle East suggest a positive selection advantage for the abnormal gene operating in this area over the last several thousand years. To date, no satisfactory explanation of this phenomenon has been made. Rather, many harmful effects of these mutations have been described. MEFV gene mutations cause familial Mediterranean fever in homozygotes, a disease associated with recurrent febrile inflammatory episodes, and death from renal failure and amyloidosis. Heterozygotes with MEFV mutations are predisposed to premature coronary disease, and rheumatologic conditions such as Behçet's disease. MEFV mutations do not appear to protect against tuberculosis. Brucellosis is still highly endemic in the Middle East because of the traditional reliance for meat and dairy production on goats and sheep, the major vectors for this zoonosis. Brucellosis causes a prolonged febrile illness lasting for months and even years, and it may have exacted a major toll among Bronze Age peasant populations in the Middle East. The gene product for MEFV, pyrin, normally inhibits interleukin-1beta production. Mutations in MEFV result in a pro-inflammatory state, with a Th1 polarization and high levels of interferon-gamma. This may actually be protective against intracellular pathogens such as brucellosis. The possible heterozygote advantage of MEFV mutations against brucellosis may therefore be a balanced polymorphism, analogous to the protective effect against malaria that maintains high levels of sickle cell trait in sub-Saharan Africa.

Animals↗
PubMed1999

Clinical, biochemical and molecular genetic features of Leber's hereditary optic neuropathy.

Leber's hereditary optic neuropathy (LHON) has traditionally been considered a disease causing severe and permanent visual loss in young adult males. In nearly all families with LHON it is associated with one of three pathogenic mitochondrial DNA (mtDNA) mutations, at bp 11778, 3460 or 14484. The availability of mtDNA confirmation of a diagnosis of LHON has demonstrated that LHON occurs with a wider range of age at onset and more commonly in females than previously recognised. In addition, analysis of patients grouped according to mtDNA mutation has demonstrated differences both in the clinical features of visual failure and in recurrence risks to relatives associated with each of the pathogenic mtDNA mutations. Whilst pathogenic mtDNA mutations are required for the development of LHON, other factors must be reponsible for the variable penetrance and male predominance of this condition. Available data on a number of hypotheses including the role of an additional X-linked visual loss susceptibility locus, impaired mitochondrial respiratory chain activity, mtDNA heteroplasmy, environmental factors and autoimmunity are discussed. Subacute visual failure is seen in association with all three pathogenic LHON mutations. However, the clinical and experimental data reviewed suggest differences in the phenotype associated with each of the three mutations which may reflect variation in the disease mechanisms resulting in this common end-point.

Age of Onset↗
PubMed2002

Recurrent thromboembolism in a patient with beta-thalassemia major associated with double heterozygosity for factor V R506Q and prothrombin G20210A mutations.

Double heterozygosity for factor V R506Q and prothrombin G20210A mutations was identified in a 24-year-old man with beta-thalassemia major. The patient experienced a first thrombotic event at the age of 19 years and three recurrent thromboses in a short time interval, the third occurring while the patient was receiving long-term anticoagulant treatment. This case suggests that patients with major thalassemia and congenital thrombophilic mutations need intensive and long-lasting anticoagulant treatment. Thus, even if thrombotic events could be explained by a hypercoagulable state observed in patients with major thalassemia, after a first thrombotic event has occurred these patients should be screened for acquired and congenital thrombophilia.

3' Untranslated Regions↗
PubMed2001

Prognostic significance of K-ras and TP53 mutations in the role of adjuvant chemotherapy on survival in patients with Dukes C colon cancer.

PURPOSE: Mutations in K-ras and TP53 genes are common in colorectal cancer. They affect biologic behavior and might influence chemotherapy susceptibility in these tumors. We investigated whether the survival of patients with Dukes C colon cancer treated with adjuvant chemotherapy is influenced by K-ras and TP53 mutations. METHODS: Mutation screening of the hot spots of the K-ras gene and of the evolutionarily conserved regions of the TP53 gene was performed by denaturing gradient gel electrophoresis technique in formalin-fixed paraffin-embedded specimens of 55 consecutive patients with Dukes C colon cancer treated with adjuvant 5-fluorouracil-based chemotherapy. The median follow-up was 47 (range, 32-66) months. RESULTS: Alterations in the mutation hot spots of K-ras were found at codon 12 (n = 11) and 13 (n = 4) in 15 of the 55 carcinomas (27 percent). No mutation was found at codon 61. Mutations of a probably causative nature in the evolutionarily conserved regions (exons 5-8) of the TP53 gene were found in 24 tumors (44 percent). K-ras and TP53 mutations were found equally in the group with recurrent disease (7/26 (26 percent) and 12/27 (44 percent), respectively) and in the group without recurrences (8/28 (24 percent) and 12/28 (43 percent), respectively). Cancer-specific survival did not differ significantly between patients with K-ras or TP53 or both mutated and nonmutated tumors, respectively (log-rank test: K-ras, P = 0.72 and TP53, P = 0.77; K-ras and TP53, P = 0.8). Also, potentially aggressive K-ras codon 12 and 13 mutations had the same survival as tumors without these mutations (log-rank test; P = 0.73). CONCLUSIONS: Patients with K-ras or TP53 or both mutated Dukes C colon tumors have the same survival as nonmutated tumors when treated with adjuvant chemotherapy. These data suggest that mutations in K-ras or TP53 alone are not prognostic indicators in patients with Dukes C colon cancer receiving adjuvant 5-Fluorouracil-based therapy.

Adult↗
PubMed2005

Familial autoinflammatory diseases: genetics, pathogenesis and treatment.

PURPOSE OF REVIEW: The systemic autoinflammatory diseases are characterized by seemingly unprovoked inflammation, without major involvement of the adaptive immune system. This review focuses mainly on a subset of these illnesses, the hereditary recurrent fevers, which include familial Mediterranean fever, the tumor necrosis factor receptor-associated periodic syndrome, the hyperimmunoglobulinemia D with periodic fever syndrome, and cryopyrin-associated periodic syndromes. This review elucidates how recent advances have impacted diagnosis, pathogenesis, and treatment. RECENT FINDINGS: More than 170 mutations have been identified in the four genes underlying the six hereditary recurrent fevers. Genetic testing has broadened the clinical and geographic boundaries of these illnesses, given rise to the concept of the cryopyrin-associated periodic syndromes as a disease spectrum, and permitted diagnosis of compound heterozygotes for mutations in two different hereditary recurrent fever genes. Genetics has also advanced our understanding of amyloidosis, a complication of the hereditary recurrent fevers, and suggested a possible role for common hereditary recurrent fever variants in other inflammatory conditions. Recent advances in molecular pathophysiology include the elucidation of the N-terminal PYRIN domain in protein-protein interactions, the description of the NALP3 (cryopyrin) inflammasome as a macromolecular complex for interleukin-1beta activation, and the identification of signaling defects other than defective receptor shedding in patients with tumor necrosis factor receptor-associated periodic syndrome. These molecular insights form the conceptual basis for targeted biologic therapies. SUMMARY: Advances in molecular genetics extend our ability to recognize and treat patients with systemic autoinflammatory diseases and inform our understanding of the regulation of innate immunity in humans.

Autoimmune Diseases↗
PubMed2001

Survival of male patients with incontinentia pigmenti carrying a lethal mutation can be explained by somatic mosaicism or Klinefelter syndrome.

Incontinentia pigmenti (IP), or "Bloch-Sulzberger syndrome," is an X-linked dominant disorder characterized by abnormalities of skin, teeth, hair, and eyes; skewed X-inactivation; and recurrent miscarriages of male fetuses. IP results from mutations in the gene for NF-kappaB essential modulator (NEMO), with deletion of exons 4-10 of NEMO accounting for >80% of new mutations. Male fetuses inheriting this mutation and other "null" mutations of NEMO usually die in utero. Less deleterious mutations can result in survival of males subjects, but with ectodermal dysplasia and immunodeficiency. Male patients with skin, dental, and ocular abnormalities typical of those seen in female patients with IP (without immunodeficiency) are rare. We investigated four male patients with clinical hallmarks of IP. All four were found to carry the deletion normally associated with male lethality in utero. Survival in one patient is explained by a 47,XXY karyotype and skewed X inactivation. Three other patients possess a normal 46,XY karyotype. We demonstrate that these patients have both wild-type and deleted copies of the NEMO gene and are therefore mosaic for the common mutation. Therefore, the repeat-mediated rearrangement leading to the common deletion does not require meiotic division. Hypomorphic alleles, a 47,XXY karyotype, and somatic mosaicism therefore represent three mechanisms for survival of males carrying a NEMO mutation.

Alleles↗
PubMed2001

Genetic alterations in tp53 in recurrent urothelial cancer: a longitudinal study.

PURPOSE: Because bladder cancer has a recurrence rate that can be as high as 90% at 2 years, we sought to clarify whether these metachronous tumors are polyclonal or monoclonal in origin. We have examined the genetic alterations of the TP53 gene in a cohort of patients with urothelial cancer who underwent multiple biopsies at different times and sites because of tumor recurrence and/or progression. We postulated that if tumor cells at different points in the natural history of the disease contain an identical mutation in the TP53 gene, this pattern could provide evidence for the monoclonality of the recurrent bladder tumors. EXPERIMENTAL DESIGN: Fifty-three biopsy specimens from 13 patients at different times and sites were selected for this study. Microdissection was used to ensure the purity of tumor cells. DNA extraction, PCR, and direct sequencing of exons 5 through 8 of the TP53 gene were conducted following protocols optimized in our laboratory. RESULTS: We found that specimens from seven patients carried tumor-specific TP53 mutations. The number of lesions in these patients ranged from two to seven, extending from 2 to 4 years. All of the seven patients displayed identical mutations in the different microdissected tumors. CONCLUSIONS: On the basis of these data, it appears that the recurrent bladder tumors originate from the same clone.

DNA Mutational Analysis↗
PubMed1997

The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis.

Tuberous sclerosis is an autosomal dominant trait in which the dysregulation of cellular proliferation and differentiation results in the development of hamartomatous growths in many organs. The TSC2 gene is one of two genes determining tuberous sclerosis. Inactivating germline mutations of TSC2 in patients with tuberous sclerosis and somatic loss of heterozygosity at the TSC2 locus in the associated hamartomas indicate that TSC2 functions as a tumour suppressor gene and that loss of function is critical to expression of the tuberous sclerosis phenotype. The TSC2 product, tuberin, has a region of homology with the GTPase activating protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in vitro. Here we show that the region of homology between tuberin and human rap1GAP and the murine GAP mSpa1 is more extensive than previously reported and spans approximately 160 amino acid residues encoded within exons 34-38 of the TSC2 gene. Single strand conformation polymorphism analysis of these exons in 173 unrelated patients with tuberous sclerosis and direct sequencing of variant conformers together with study of additional family members enabled characterisation of disease associated mutations in 14 cases. Missense mutations, which occurred in exons 36, 37 and 38 were identified in eight cases, four of whom shared the same recurrent change P1675L. Each of the five different missense mutations identified was shown to occur de novo in at least one sporadic case of tuberous sclerosis. The high proportion of missense mutations detected in the region of the TSC2 gene encoding the GAP-related domain supports its key role in the regulation of cellular growth.

Amino Acid Sequence↗
PubMed2004

Relapse after more than 20 years of follow-up for epithelial ovarian carcinoma.

BACKGROUND: Very late relapse of ovarian cancer is unusual and may present with atypical symptoms. CASES: We diagnosed 3 cases of relapse occurring after more than 20 years of follow-up. In the first case, the first recurrence was diagnosed by an appendicitis syndrome. With the second recurrence, small pelvic nodules were detected by fluorodeoxyglucose scintigraphy, whereas other imaging method results were negative. In the second case, a nodule in the axilla revealed the recurrence, and imaging methods confirmed multiple metastasis. In the third case, the patient presented with paroxysmal abdominal pain, and fluorodeoxyglucose scintigraphy showed a tiny lesion. CONCLUSION: Late relapses of ovarian cancer raise the issue of regrowth of dormant cells or the development of a new primary cancer. The absence of family history and BRCA gene mutations in these 3 patients favor late recurrence. Fluorodeoxyglucose scintigraphy was useful for diagnosis, particularly of small lesions not visible by classic imaging methods.

Abdominal Pain↗
PubMed2002

Prevalence of genetic markers for thrombophilia in recurrent pregnancy loss.

BACKGROUND: The genetic predispositions to venous thrombosis such as factor V Leiden (FVL) mutation (Arg 506 Gln), prothrombin (FII) gene mutation (G20210A), and mutation of the methylenetetrahydrofolate reductase (MTHFR) gene (C677T) have been reported to be associated with recurrent pregnancy loss. This paper examines the prevalence of markers for genetic thrombophilias in women with recurrent miscarriage. METHODS: The prevalence of FVL, FII G20210A and MTHFR C677T was compared in 108 women with three or more pregnancy losses either exclusively in the first trimester, or mixed first and second trimester losses, with the prevalence found in 82 fertile parous control women without miscarriages. Markers for the thrombophilias were assessed by PCR analysis. RESULTS: Twenty-three of the 108 patients (21.3%), had thrombophilia markers, which was similar to the proportion of patients in the control group (20.7%) with these markers. The prevalences of FVL and FII G20210A were lower in the study group than in the control group (3.7 versus 6.1% for FVL and 4.6 versus 6.1% for FII respectively); however, the difference was not statistically significant. In contrast, the prevalence of MTHFR C677T was higher in the study group than the control population (13 versus 8.5% respectively), but this difference was not statistically significant. There was no statistically significant prevalence of any particular thrombophilia in patients with previous first and second trimester pregnancy losses compared with patients with first trimester losses alone. CONCLUSION: Thrombophilia was not found to be associated with recurrent pregnancy loss.

Abortion, Habitual↗
PubMed2004

Risk of pancreatitis with mutation of the cystic fibrosis gene.

BACKGROUND: Between 5% and 15% of patients with recurrent pancreatitis have no identified etiology after routine investigation and advanced endoscopic evaluation. OBJECTIVE: To determine whether mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene is a risk factor for idiopathic pancreatitis. METHODS: We compared the frequency of CFTR mutations as measured by DNA probe analysis in a case group of persons with idiopathic pancreatitis and a control group without pancreatitis, all of whom underwent endoscopic retrograde cholangiopancreatography. A separate analysis compared the prevalence of CFTR mutations between the case group and controls with pancreatitis of known etiology. A subgroup comparison was made between cases of pancreas divisum with pancreatitis and controls with pancreas divisum and no pancreatitis. RESULTS: CFTR mutations were present in 19 (19%) of 96 cases and 7 (3.5%) of 198 controls without pancreatitis (odds ratio, OR = 6.7; 95% CI, 2.8-16.3; p < 0.00001). Compared to the controls with a known cause of pancreatitis (N = 78), cases had a higher prevalence of CFTR mutations (19% vs 2.6%, OR = 9.4; CI, 2.1-41.7; p= 0.0005). Among subjects with pancreas divisum, CFTR mutations were present in 8 (22%) of 37 cases compared to 0 (0%) of 20 controls (OR = 11.8; CI, 8.9-14.7; p= 0.02). CONCLUSION: The risk of idiopathic pancreatitis is greater among persons with CFTR mutations as compared to persons without CFTR mutations. Among persons with pancreas divisum, CFTR mutations appear to increase the risk for pancreatitis.

Adolescent↗
PubMed2004

Hereditary pancreatitis in a family of Aboriginal descent.

Hereditary pancreatitis is an autosomal dominant condition characterized by recurrent episodes of acute pancreatitis, usually starting in childhood. We present a family who was ascertained when an 11-year-old girl presented with an episode of acute pancreatitis. Her father and other family members had also had recurrent bouts of acute pancreatitis. Genetic testing revealed a pathogenic mutation in the cationic trypsinogen gene in the proband, her father and her paternal grandmother. As far as we are aware, this is the first Aboriginal kindred with mutation-proven hereditary pancreatitis. Hereditary pancreatitis is an important differential diagnosis to consider in a patient with recurrent episodes of acute pancreatitis with no obvious precipitating cause. This family is of Aboriginal descent and the implications of the family's background are also discussed when considering the aetiology of the condition. We emphasize the need to ascertain a full family history from patients with a history of repeated episodes of acute pancreatitis and also emphasize the need to avoid ethnic stereotypes when assessing patients.

Child↗
PubMed2002

Complex cytogenetic abnormalities including telomeric associations and MEN1 mutation in a pediatric ependymoma.

Ependymomas are neuroectodermal tumors of the brain and spinal cord. Some recurrent cytogenetic aberrations have been reported in these tumors, including alterations involving chromosomes 22, 6, and 11. However, consistent molecular alterations have not been identified in ependymal tumors. We studied a recurrent ependymoma in a 3-year-old patient by standard cytogenetic and molecular analysis of TP53 and MEN1 genes. In the present case, we found many of the cytogenetic features previously described as being recurrent in ependymomas, including unstable telomeric alterations. Furthermore, we detected a novel acquired heterozygous mutation in the MEN1 gene. The chromosomal instability produced by the telomeric alterations and the mutation in the MEN1 gene could be important events in the tumorigenesis of ependymomas.

Base Sequence↗

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