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Hypereosinophilic syndrome associated with heterozygous factor V gene mutation: an unusual combination resulting in an acute coronary syndrome and recurrent cerebral stroke-a case report.

The authors report the first case of a patient with a hypereosinophilic syndrome associated with heterozygous factor V gene mutation, resulting in an acute coronary syndrome and recurrent cerebral stroke despite effective anticoagulation. A 40-year-old man presented with an acute coronary syndrome accompanied by a brachiofacial right-sided hemiparesis and dysarthria. Diagnosis of a hypereosinophilic syndrome was established by blood testing, myocardial biopsy, and bone marrow analysis. Eosinophilic infiltration was present in the myocardium, accompanied by proliferation in the endomyocardium and a pneumonic infiltrate. Although effective anticoagulation with heparin was administered, a recurrent stroke occurred while blood eosinophils were being normalized by corticosteroid treatment. A coexisting heterozygosity of the factor V mutation was demonstrated, and it is hypothesized that this might have contributed to the recurrent thromboembolic episodes. In patients with hypereosinophilic syndrome and recurrent thromboembolic episodes, other thrombophilic diseases, including factor V mutations, should be considered, and long-term coagulation should be contemplated.

Adult↗
PubMed1997

The risk of recurrent venous thromboembolism in patients with an Arg506-->Gln mutation in the gene for factor V (factor V Leiden).

BACKGROUND: A recently discovered mutation in coagulation factor V (Arg506-->Gln, referred to as factor V Leiden), which results in resistance to activated protein C, is found in approximately one fifth of patients with venous thromboembolism. However, the risk of recurrent thromboembolism in heterozygous carriers of this genetic abnormality is unknown. METHODS: We searched for factor V Leiden in 251 unselected patients with a first episode of symptomatic deep-vein thrombosis diagnosed by venography. The patients were followed prospectively for a mean of 3.9 years to determine the frequency of recurrent venous thrombosis and pulmonary embolism. RESULTS: Factor V Leiden was found in 41 of the patients (16.3 percent; 95 percent confidence interval, 11.8 to 20.9 percent). The cumulative incidence of recurrent venous thromboembolism after follow-up of up to eight years was 39.7 percent (95 percent confidence interval, 22.8 to 56.5 percent) among carriers of the mutation, as compared with 18.3 percent (95 percent confidence interval, 12.3 to 24.3 percent) among patients without the mutation (hazard ratio, 2.4; 95 percent confidence interval, 1.3 to 4.5; P<0.01). CONCLUSIONS: The risk of recurrent thromboembolic events is significantly higher in carriers of factor V Leiden than in patients without this abnormality. Large trials assessing the risk-benefit ratio of long-term anticoagulation in carriers of the mutation who have had a first episode of venous thromboembolism are indicated.

Adult↗
PubMed2003

A WW domain binding region in methyl-CpG-binding protein MeCP2: impact on Rett syndrome.

Rett syndrome is a dominant neurological disorder caused by loss-of-function mutations of methyl-CpG-binding protein 2 (MeCP2). MeCP2 is an abundant chromatin-associated protein that contains two well characterized domains. Through an N-terminal domain it recognizes methyl-CpGs and binds to nonmethylated DNA. A domain in the middle of the protein can act as a transcriptional repressor in transient transfection studies. The C-terminal region of the protein is equally essential for the function of MeCP2, as documented by recurrently found frameshift mutations. However, little is known about its functional role. Here we mapped a domain within MeCP2 capable of binding specifically to Group II WW domains of splicing factors formin-binding protein (FBP) 11 and HYPC. Binding was assessed by glutathione S-transferase pull-down assays and coimmunoprecipitation assays. The Group II WW domain binding region was localized from residue 325 to the C-terminus, with the interacting proline-rich sequence at its center. We then used comparison with genotype-phenotype studies in Rett syndrome patients to evaluate the relevance of Group II WW domain interactions of MeCP2 for pathogenesis. Truncation of the WW domain binding region by 48 C-terminal amino acids (to residue 438), causing Rett syndrome, resulted in reduced or loss of WW domain binding activity. Truncation to residue 400, representing a large group of frameshift mutations accounting for approx. 10% of Rett syndrome cases, abolished WW domain binding activity completely. On the other hand, two benign missense mutations did not affect binding. Furthermore, a short C-terminal truncation and an internal deletion, both causing mild to moderate mental retardation in males, were associated with weak or loss of WW domain binding activity.

Animals↗
PubMed2004

Clinical assessment and mutation analysis of Kallmann syndrome 1 (KAL1) and fibroblast growth factor receptor 1 (FGFR1, or KAL2) in five families and 18 sporadic patients.

We report on the clinical and molecular findings in 25 males and three females with Kallmann syndrome (KS) aged 10-53 yr. Ten males were from five families, and the remaining 15 males and three females were apparently sporadic cases. Molecular studies were performed for Kallmann syndrome 1 (KAL1) and fibroblast growth factor receptor 1 (FGFR1, also known as KAL2) by sequence analysis for all the coding exons, by PCR-based deletion analysis, and by fluorescence in situ hybridization (FISH) analysis, showing six novel and two recurrent intragenic KAL1 mutations in seven familial and four sporadic male cases and two novel intragenic FGFR1 mutations in two sporadic male cases. In addition, submicroscopic deletions at Xp22.3 involving VCX-A, STS, KAL1, and OA1 were identified in three familial cases and one sporadic male case affected by a contiguous gene syndrome. Clinical assessment in the 15 males with KAL1 mutations showed normal and borderline olfactory function in two males and right-side dominant renal lesion in seven males, in addition to variable degrees of hypogonadotropic hypogonadism (HH) in all the 15 males and olfactory dysfunction in 13 males. The two males with FGFR1 mutations had HH and anosmia and lacked other features. Clinical features in the remaining 11 cases with no demonstrable KAL1 or FGFR1 mutations included right renal aplasia in one female, cleft palate in one male, cleft palate and perceptive deafness in one male, and dental agenesis and perceptive deafness in one male, in addition to a variable extent of HH and olfactory dysfunction. The results suggest the following: 1) KAL1 mutations might be more prevalent in the Japanese patients than previously estimated in the Caucasian patients and can be associated with apparently normal olfactory function; 2) FGFR1 mutations account for approximately 10% of KS patients, as previously reported in the Caucasian patients, and can result in HH and olfactory dysfunction-only phenotype; and 3) renal aplasia, which is characteristic of KAL1 mutations, and cleft palate and dental agenesis, which are characteristic of FGFR1 mutations, can occur in patients without KAL1 and FGFR1 mutations.

Adolescent↗
PubMed1999

Variant Bernard-Soulier syndrome due to homozygous Asn45Ser mutation in the platelet glycoprotein (GP) IX in seven patients of five unrelated Finnish families.

Bernard-Soulier syndrome (BSS), a rare bleeding disorder with macrothrombocytopenia, is caused by a defect of the platelet glycoprotein (GP) Ib/IX/V complex. Here we report a variant form of BSS in eleven patients of five unrelated families who originate from a particular area of Finland. The differential diagnosis from idiopathic thrombocytopenic purpura was difficult. Bleeding symptoms were epistaxis and haematomas debuting in childhood, but no spontaneous, severe bleeding episodes were reported. The platelet count varied from 43 to 81x10(9)/l. Screening the entire GP Ibalpha, GP Ibbeta, GP IX and GP V genes revealed a recurrent homozygous Asn45Ser mutation in GP IX in all probands. Flow cytometry showed markedly reduced expression of GP Ib (<10%), and only moderately reduced expression of GP IX (24-36%) and GP V (38-49%). The expression of subunits seemed to vary independently from the normal polymorphisms. Heterozygotes did not differ significantly from controls by their GP Ib/IX/V expression. Since the Asn45Ser mutation has also been reported in three other kindreds of northern and central European origin, this study reveals that instead of being a mutation hot spot, it may be ancient and scattered in Europe. Moderate, chronic thrombocytopenia should be carefully studied to diagnose variant BSS correctly from treatment resistant idiopathic thrombocytopenia.

Amino Acid Substitution↗
PubMed1997

Expression, purification and kinetic characterization of wild-type human ornithine transcarbamylase and a recurrent mutant that produces 'late onset' hyperammonaemia.

Ornithine Transcarbamylase Deficiency, an X-linked disorder, is the most common cause of inherited urea cycle disorders. Approx. 90 mutations that produce reduced levels of ornithine transcarbamylase (OTCase) activity have been identified in patients [Tuchman (1993) Hum. Mutat. 2, 174-178; Tuchman and Plante (1995) Hum. Mutat. 5, 293-295]. A model of the three-dimensional structure of OTCase, developed on the basis of its homology to the catalytic subunit of Escherichia coli aspartate transcarbamylase (ATCase) [Tuchman, Morizono, Reish, Yuan and Allewell (1995) J. Med. Genet. 32, 680-688], and in good agreement with the crystal structure of Pseudomonas aeruginosa OTCase [Villeret, Tricot, Stalon and Dideberg (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 10762-10766], indicates that many mutations that produce severe clinical symptoms are at the active site or buried in the interior of the protein. However, one of the few recurrent mutations, R277W, an alteration that produces a milder phenotype of ornithine transcarbamylase deficiency, is located in the model in a loop remote from the active site that is analogous to a similar loop (the 240's loop, a flexible loop of the catalytic chain of Escherichia coli aspartate transcarbamylase, comprised of residues 230-250) of ATCase. Human wild-type OTCase and the R277W mutant have been cloned and overexpressed in E. coli and a rapid and efficient purification method utilizing the bisubstrate analogue, Ndelta-(phosphonacetyl)-L-ornithine, has been developed and used to purify both proteins. Gel chromatography indicates both are trimeric. The pH dependence of the kinetic parameters of the wild-type enzyme is similar to that of E. coli OTCase [Kuo, Herzberg and Lipscomb (1985) Biochemistry 24, 4754-4761], suggesting that its catalytic mechanism is similar, although its maximal activity is approx. 10-fold less. Compared with the wild-type, the R277W mutant has nearly 70-fold lower affinity for L-ornithine, shows no substrate inhibition, and its thermal stability is reduced by 5 degrees C. Its reduced affinity for L-ornithine, which in turn results in lower activity at physiological concentrations of ornithine, as well as its reduced stability, may contribute to the clinical effects that it produces.

Ammonia↗
PubMed1992

A novel homozygous missense mutation in the protein C (PROC) gene causing recurrent venous thrombosis.

A novel homozygous CCC----CTC (Pro 247----Leu) substitution was detected in the protein C genes of a patient, born to consanguineous parents, with inherited type 1 protein C deficiency and recurrent venous thrombosis. Since one of four heterozygous relatives was also clinically affected, the condition appears to be inherited as an incompletely recessive trait in this family.

Base Sequence↗
PubMed2001

Frequent beta-catenin mutations in juvenile nasopharyngeal angiofibromas.

Juvenile nasopharyngeal angiofibromas (JNAs) are locally aggressive vascular tumors occurring predominantly in adolescent males. The pathogenesis of JNAs is unknown. Recently, JNAs have been reported to occur at increased frequency among patients with familial adenomatous polyposis, suggesting that alterations of the adenomatous polyposis coli (APC)/beta-catenin pathway might also be involved in the pathogenesis of sporadic JNAs. We analyzed somatic beta-catenin and APC gene mutations in 16 sporadic JNAs from nonfamilial adenomatous polyposis patients using immunohistochemistry for beta-catenin, and direct DNA sequencing for exon 3 of the beta-catenin gene and the mutation cluster region of the APC gene. Nuclear accumulation of beta-catenin was diffusely present in the stromal cells but not in the endothelial cells of all 16 JNAs. Activating beta-catenin gene mutations were present in 75% (12 of 16) of JNAs. Six JNA patients also had recurrent tumors after surgery, and in all cases the beta-catenin gene status of the recurrent JNA was identical to the initial tumor. No mutations in the mutation cluster region of the APC gene were detected in the four JNAs without beta-catenin mutations. The high frequency of beta-catenin mutations in sporadic JNAs and the presence of identical beta-catenin gene mutations in recurrent tumors indicates that activating beta-catenin gene mutations are important in the pathogenesis of JNAs. The immunohistochemical localization of beta-catenin only to the nuclei of stromal cells further suggests that the stromal cells, rather than endothelial cells, are the neoplastic cells of JNAs.

Adolescent↗
PubMed1991

Clinical management issues in males with sex chromosomal mosaicism and discordant phenotype/sex chromosomal patterns.

The recent availability of Y DNA probes has made it possible to identify two forms of 46,XX male syndrome: Y DNA positive and Y DNA negative. The Y DNA positive male results from a X;Y translocation with a low recurrence risk; the Y DNA negative males are due to a mutation with a high recurrence risk. 46,XX males and mosaic forms are phenotypically indistinguishable. A review of the case histories for 11 individuals indicates that affected males have highly variable genital and nongenital phenotypes. Physical findings may be clearly apparent or nonexistent. With the exception of external genitalia, the basis for this variability is unknown. It may be related to differences in Y chromatin expression as the result of variable inactivation of the X chromosomes, or to the existence of minor deletions or point mutations secondary to an exchange of genetic material. Common and uncommon clinical problems in these individuals require evaluation and follow-up care that is provided through a cooperative, interdisciplinary approach.

Adolescent↗
PubMed2000

Mutations in the CNGB3 gene encoding the beta-subunit of the cone photoreceptor cGMP-gated channel are responsible for achromatopsia (ACHM3) linked to chromosome 8q21.

Achromatopsia is an autosomal recessive disorder featuring total colour blindness, photophobia, reduced visual acuity and nystagmus. While mutations in the CNGA3 gene on chromosome 2q11 are responsible for achromatopsia in a subset of patients, previous linkage studies have localized another achromatopsia locus, ACHM3, on chromosome 8q21. Using achromatopsia families in which CNGA3 mutations have been excluded, we refined the ACHM3 locus to a 3.7 cM region enclosed by markers D8S1838 and D8S273. Two yeast artificial chromosome (YAC) contigs covering nearly the entire ACHM3 interval were constructed. Database searches with YAC content sequences identified two overlapping high throughput genomic sequencing phase (HTGS) entries which contained sequences homologous to the murine cng6 gene encoding the putative beta-subunit of the cone photoreceptor cGMP-gated channel. Using RT-PCR and RACE, we identified and cloned the human cDNA homologue, designated CNGB3, which encodes an 809 amino acid polypeptide. Northern blot analysis revealed a major transcript of approximately 4.4 kb specifically expressed in the retina. The human CNGB3 gene consists of 18 exons distributed over approximately 200 kb of genomic sequence. Analysis of the CNGB3 gene in achromats revealed six different mutations including a missense mutation (S435F), two stop codon mutations (R203X and E336X), a 1 bp and an 8 bp deletion (1148delC and 819-826del) and a putative splice site mutation of intron 13. The 1148delC mutation was identified recurrently in several families, and in total was present on 11 of 22 disease chromosomes segregating in our families.

Amino Acid Sequence↗
PubMed2002

Spectrum and expression analysis of KRIT1 mutations in 121 consecutive and unrelated patients with Cerebral Cavernous Malformations.

Cerebral Cavernous Malformations (CCM/MIM 604214) are vascular malformations characterised by abnormally enlarged capillary cavities without intervening brain parenchyma. Clinical manifestations include seizures, cerebral haemorrhages and focal neurological deficits. They occur as a sporadic or autosomal dominant condition. Most often, sporadic cases have only one lesion and familial cases are characterised by a high frequency of multiple lesions. Three CCM loci were previously mapped on 7q (CCM1), 7p (CCM2) and 3q (CCM3) and CCM1 gene was identified as coding Krit1, a protein of unknown function, which was shown initially to interact in yeast two hybrid assays with Rap1A, a small ras GTPase and more recently to Icap1alpha, a modulator of beta1 integrin signal transduction. Herein, we screened KRIT1 gene in 121 unrelated, consecutively recruited, CCM probands having at least one affected relative and/or showing multiple lesions on cerebral MRI. Fifty-two of these probands (43%) were shown to carry a KRIT1 mutation. Forty-two distinct mutations were identified including six recurrent ones. Three-quarters of these mutations were located in the C-terminal half of the gene, mostly within exons 13, 15 and 17. All of them are predicted to lead to a premature stop codon. No missense mutation was identified. The only two nucleotide substitutions predicted to be missense mutations led in fact to an abnormal splicing and a premature stop codon. Altogether these data suggest that KRIT1 mRNA decay due to the presence of premature stop codons and Krit1 haploinsufficiency may be the underlying mechanism of CCM.

DNA Mutational Analysis↗
PubMed2002

Recurrent deep venous thrombosis caused by congenital interruption of the inferior vena cava and heterozygous factor V Leiden mutation.

A case of a 44-year-old patient with recurrent deep venous thrombosis (DVT) caused by congenital dysgenesis of the inferior vena cava (IVC) in coincidence with heterozygous factor V Leiden mutation is presented. The IVC malformation was a fortuitous finding because the vascular malformation of the collateral draining thoracic veins were suspected to be a malignant mass in chest X-ray. This vascular abnormality is a rare finding but recent epidemiological research suggests that there may be an association between the congenital absence of the IVC and DVT. In our case, the patient is even at higher risk combining the malformation probably affecting venous blood flow and the hypercoagulabilic state by heterozygous presence of the factor V Leidenmutation.

Adult↗
PubMed2004

Identification of KIF21A mutations as a rare cause of congenital fibrosis of the extraocular muscles type 3 (CFEOM3).

PURPOSE: Three congenital fibrosis of the extraocular muscles phenotypes (CFEOM1-3) have been identified. Each represents a specific form of paralytic strabismus characterized by congenital restrictive ophthalmoplegia, often with accompanying ptosis. It has been demonstrated that CFEOM1 results from mutations in KIF21A and CFEOM2 from mutations in PHOX2A. This study was conducted to determine the incidence of KIF21A and PHOX2A mutations among individuals with the third CFEOM phenotype, CFEOM3. METHODS: All pedigrees and sporadic individuals with CFEOM3 in the authors' database were identified, whether the pedigrees were linked or consistent with linkage to the FEOM1, FEOM2, and/or FEOM3 loci was determined, and the appropriate pedigrees and the sporadic individuals were screened for mutations in KIF21A and PHOX2A. RESULTS: Twelve CFEOM3 pedigrees and 10 CFEOM3 sporadic individuals were identified in the database. The structures of eight of the pedigrees permitted the generation of meaningful linkage data. KIF21A was screened in 17 probands, and mutations were identified in two CFEOM3 pedigrees. One pedigree harbored a novel mutation (2841G-->A, M947I) and one harbored the most common and recurrent of the CFEOM1 mutations identified previously (2860C-->T, R954W). None of CFEOM3 pedigrees or sporadic individuals harbored mutations in PHOX2A. CONCLUSIONS: The results demonstrate that KIF21A mutations are a rare cause of CFEOM3 and that KIF21A mutations can be nonpenetrant. Although KIF21A is the first gene to be associated with CFEOM3, the results imply that mutations in the unidentified FEOM3 gene are the more common cause of this phenotype.

DNA Mutational Analysis↗
PubMed2003

Late recurrence of inflammatory first-stage lesions in incontinentia pigmenti: an unusual phenomenon and a fascinating pathologic mechanism.

BACKGROUND: Incontinentia pigmenti (IP) is an X-linked genodermatosis that is manifested by neonatal inflammatory vesicles localized along the lines of Blaschko. These lesions usually clear spontaneously within a few months, leaving hyperpigmentation. Ophthalmologic and neurologic symptoms can be associated with IP. Late recurrences of the first-stage inflammatory lesions after the initial rash are uncommon and have been reported infrequently. The mechanism involved in this phenomenon is unclear. However, the recent identification of NEMO/IKKgamma as the gene responsible for IP sheds new light on its pathophysiologic origins. OBSERVATIONS: We report 5 cases of children who experienced episodes of late reactivation of IP. In all cases, the recurrences occurred on the previously hyperpigmented streaks several months or years after resolution of the initial eruptions. In most cases, the recurrences were preceded by an infectious episode. CONCLUSIONS: These IP recurrences suggest that mutated cells can persist a long time in the epidermis. We theorize that infections trigger the reactivations. The NEMO/IKKgamma gene encodes a protein essential in nuclear factor kappaB activation, which is required for resistance to tumor necrosis factor alpha-induced apoptosis. We discuss the role of a proinflammatory cytokine such as tumor necrosis factor alpha as a triggering factor for the reactivation.

Biopsy, Needle↗
PubMed2006

Clinical characteristics of paroxysmal nonkinesigenic dyskinesia in Serbian family with Myofibrillogenesis regulator 1 gene mutation.

The aim of this study was to describe the clinical features of a large Serbian family with paroxysmal nonkinesigenic dyskinesia (PNKD) and one of the two previously described mutations in the Myofibrillogenesis regulator 1 gene (MR-1), which causes an alanine-to-valine substitution at position 9. In 5 examined out of 12 affected family members, attacks of dyskinesias appeared in the first 6 months of life. Both frequency and severity of attacks showed an age-dependent incremental-decremental pattern with a peak between 13 to 15 years of age. They were frequently precipitated by stress, caffeine, fever, hunger, tiredness, as well as abrupt changes in temperature. Three of our patients differentiated two types of attacks: mild (120-180 minutes), with a predominance of functionally insignificant choreoathetoid movements, and severe ( approximately 15-30 minutes), characterized by disabling dystonic and choreic movements of the extremities, trunk, and face. Sleep was the most reliable factor to discontinue an attack. This Serbian family further demonstrates that recurrent MR-1 mutations are associated with PNKD worldwide, which will affect genetic testing.

Adolescent↗
PubMed2006

FBN1, TGFBR1, and the Marfan-craniosynostosis/mental retardation disorders revisited.

The recent identification of TGFBR2 mutations in Marfan syndrome II (MFSII) [Mizuguchi et al. (2004); Nat Genet 36:855-860] and of TGFBR1 and TGFBR2 mutations in Loeys-Dietz aortic aneurysm syndrome (LDS) [Loeys et al. (2005); Nat Genet 37:275-281] [OMIM 609192] has provided direct evidence of abnormal signaling in transforming growth factors beta (TGF-beta) in the pathogenesis of Marfan syndrome (MFS). In light of this, we describe the phenotypes and genotypes of five individuals. Patient 1 had MFS and abnormal cranial dura. Patient 2 had severe early onset MFS and an abnormal skull. Patients 3 and 4 had probable Furlong syndrome (FS). Patient 5 had marfanoid (MD) features, mental retardation (MR), and a deletion of chromosome 15q21.1q21.3. All patients had a condition within the MFS, MD-craniosynostosis (CS) or MD-MR spectrum. The names of these entities may become redundant, and instead, come to be considered within the spectrum of TGF-beta signaling pathway disorders. Two recurrent heterozygous FBN1 mutations were found in Patients 1 and 2, and an identical novel heterozygous de novo TGFBR1 mutation was found in Patients 3 and 4, in whom altered fibrillin-1 processing was demonstrated previously [Milewicz et al. (2000); Am J Hum Genet 67:279]. A heterozygous FBN1 deletion was found in Patient 5. These findings support the notion that perturbation of extracellular matrix homeostasis and/or remodeling caused by abnormal TGF-beta signaling is the core pathogenetic mechanism in MFS and related entities including the MD-CS syndromes.

Abnormalities, Multiple↗