Papers by Ivo M Kremensky
Human Mutation, Apr 26, 2000
Sarcoglycanopathies, affecting the dystrophin-associated sarcoglycan (SG) complex, are a heteroge... more Sarcoglycanopathies, affecting the dystrophin-associated sarcoglycan (SG) complex, are a heterogeneous group of neuromuscular disorders. A subgroup of these disorders, limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive disorder, clinically manifested as an early onset, severe Duchenne-like muscular dystrophy. LGMD2C is caused by mutations in the gamma-SG gene, localized on 13q12. Recently, a number of mutations have been described in that gene, among which C283Y, a "private" Gypsy mutation (eight codons before the 3' end of the gene) is detected. In this article, we report on a single-strand conformation polymorphism (SSCP) method for fast C283Y mutation detection, using direct dry blood spot amplification. The method permits a large number of samples to be easily screened. To check heterozygote carriers of C283Y mutation among Gypsy population in Bulgaria, the SSCP analysis was applied on 400 Gypsy newborns from northeast Bulgaria. Our results show 2.25% of heterozygosity, which means that 1 in 50 Gypsies carries the mutation. Moreover, new SSCP migration patterns were detected that revealed two polymorphisms still unavailable in the literature. One of these changes was 984G-->A, leading to substitution of conserved serine at position 287 with asparagine and the second one is 1049C-->G at the 3' UTR (untranslated region). The present data could help the understanding the role of these sequences for the protein function.
Journal of Medical Genetics, Dec 1, 1990
RFLP haplotypes and common mutations in the phenylalanine hydroxylase gene have been studied in a... more RFLP haplotypes and common mutations in the phenylalanine hydroxylase gene have been studied in a group of 29 Bulgarian PKU families. Haplotype distribution differs from that in other European populations, with a predominance of haplotypes 2 and 6 and a total absence of haplotype 3. The amino acid substitutiou in codon 408 is the most frequent molecular defect. The splicing defect in intron 12 is not found in Bulgarian PKU patients. Testing for three mutations, reported to be common among haplotype 1 and 4 alleles, has shown that they occur less frequently ini Bulgarian PKU patients. Screening with five pairs of allele specific oligonucleotides failed to show the mutation in 590/o of the patients. These findings-add to the evidence that PKU is heterogeneous and that significant interpopulation differences exist. At present, DNA data cannot be used as an aid in early clinical classification and prognosis of hyperphenylalaninaemia in Bulgaria. Neonatal screening in Bulgaria, with nearly one million neonates tested, has shown an incidence of classical phenylketonuria (PKU) of 1 in 21 000 and a relatively high frequency of mild hyperphenylalaninaemia (HPA) with a PKU/HPA ratio of 1/2. Experience has shown that both parental anxiety and non-compliance with the diet are frequent problems which require prompt classification of the phenylalaninaemias detected by the screening. Studies of DNA polymorphisms in Danish HPA families established a correlation between the patients'
Case reports in genetics, Jul 25, 2018
Congenital muscle dystrophies (CMD) are genetically and clinically heterogeneous hereditary myopa... more Congenital muscle dystrophies (CMD) are genetically and clinically heterogeneous hereditary myopathies mainly with autosomal recessive type of inheritance. The most common form worldwide is considered to be merosin-deficient muscle dystrophy type 1A, called MDC1A (due to laminin-2 defects as a result of LAMA2 gene mutation), accounting for 30-40% of total cases of CMD. The exact molecular and clinical diagnoses, respectively, are a prerequisite for the most effective treatment; sometimes orphan drugs exist for some rare diseases. One of such drugs is Tarix, which was FDA approved and announced in 2016 for treatment of MDC1A. Here we present a patient diagnosed postmortem as having early-onset LAMA2-related muscular dystrophy as a result of mutations in LAMA2, identified by Sanger sequencing in his parents: a novel nonsense mutation c.4452T>A in exon 31, identified in the mother, and a known pathogenic nonsense mutation c.2901C>A in exon 21, detected in the father. The truncating nature of both nonsense mutations made the clinical presentation severe and the outcome fatal. Genetic analysis in such cases of muscle dystrophy is of utmost impact, because it makes the correct diagnosis with at least some specific options for treatment, makes the prognosis depending on the severity of mutation discovered, determines reproductive risk, and offers prophylaxis in the family by means of prenatal or preimplantation diagnostics.
Human Mutation, May 1, 2000
Sarcoglycanopathies, affecting the dystrophin-associated sarcoglycan (SG) complex, are a heteroge... more Sarcoglycanopathies, affecting the dystrophin-associated sarcoglycan (SG) complex, are a heterogeneous group of neuromuscular disorders. A subgroup of these disorders, limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive disorder, clinically manifested as an early onset, severe Duchenne-like muscular dystrophy. LGMD2C is caused by mutations in the gamma-SG gene, localized on 13q12. Recently, a number of mutations have been described in that gene, among which C283Y, a "private" Gypsy mutation (eight codons before the 3' end of the gene) is detected. In this article, we report on a single-strand conformation polymorphism (SSCP) method for fast C283Y mutation detection, using direct dry blood spot amplification. The method permits a large number of samples to be easily screened. To check heterozygote carriers of C283Y mutation among Gypsy population in Bulgaria, the SSCP analysis was applied on 400 Gypsy newborns from northeast Bulgaria. Our results show 2.25% of heterozygosity, which means that 1 in 50 Gypsies carries the mutation. Moreover, new SSCP migration patterns were detected that revealed two polymorphisms still unavailable in the literature. One of these changes was 984G-->A, leading to substitution of conserved serine at position 287 with asparagine and the second one is 1049C-->G at the 3' UTR (untranslated region). The present data could help the understanding the role of these sequences for the protein function.
Public Health Genomics, 2002
Limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive disorder caused by muta... more Limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive disorder caused by mutations in the γ-sarcoglycan gene. A ‘private’ Gypsy C283Y mutation was detected in this gene. Recently, a number of LGMD2C-affected families belonging to a Xoroxane Gypsy group have been detected in eastern Bulgaria and all of these cases were due to the same mutation. We have screened 300 unrelated individuals of reproductive age from this high-risk Xoroxane Gypsy group, settled in Sliven. The genetic test by PCR-SSCP analysis for the C283Y mutation revealed a carrier frequency of 7.7%. The screened sample was ethnically not homogeneous. It was divided in ethnonym groups on the basis of social and economic status, language characteristics and trades. We found that the C283Y was not randomly distributed among the Gypsy subgroups. The disease seemed to be limited to the Xoroxane Gypsy group and geographically localized in eastern Bulgaria.
Human Genetics, Oct 1, 1991
A new mutation (CGA to TGA) in codon 261 of exon 7 of the phenylalanine hydroxylase gene transfor... more A new mutation (CGA to TGA) in codon 261 of exon 7 of the phenylalanine hydroxylase gene transforms Arg261 to a stop codon in two unrelated patients of German and Turkish origin. The different ethnic backgrounds and the different polymorphic characteristics of the two mutant alleles suggest an independent origin of the mutation. This is the second defect detected in codon 261 of the phenylalanine hydroxylase gene, a codon that thus appears to be a mutation hot spot.
Human Mutation, 1999
Sarcoglycanopathies, affecting the dystrophin-associated sarcoglycan (SG) complex, are a heteroge... more Sarcoglycanopathies, affecting the dystrophin-associated sarcoglycan (SG) complex, are a heterogeneous group of neuromuscular disorders. A subgroup of these disorders, limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive disorder, clinically manifested as an early onset, severe Duchenne-like muscular dystrophy. LGMD2C is caused by mutations in the gamma-SG gene, localized on 13q12. Recently, a number of mutations have been described in that gene, among which C283Y, a "private" Gypsy mutation (eight codons before the 3' end of the gene) is detected. In this article, we report on a single-strand conformation polymorphism (SSCP) method for fast C283Y mutation detection, using direct dry blood spot amplification. The method permits a large number of samples to be easily screened. To check heterozygote carriers of C283Y mutation among Gypsy population in Bulgaria, the SSCP analysis was applied on 400 Gypsy newborns from northeast Bulgaria. Our results show 2.25% of heterozygosity, which means that 1 in 50 Gypsies carries the mutation. Moreover, new SSCP migration patterns were detected that revealed two polymorphisms still unavailable in the literature. One of these changes was 984G-->A, leading to substitution of conserved serine at position 287 with asparagine and the second one is 1049C-->G at the 3' UTR (untranslated region). The present data could help the understanding the role of these sequences for the protein function.
Revue Neurologique, Dec 1, 2005
Biotechnology & Biotechnological Equipment, 2008
Numerous mutations in the Factor VIII gene leading to haemophilia A have been identified, includi... more Numerous mutations in the Factor VIII gene leading to haemophilia A have been identified, including point mutations, deletions, insertions and rearrangements. In about half of the patients with severe disease (25 % of all cases) large DNA inversions are present. These rearrangements can be detected by Southern blot assay. Here we present a novel PCR-generated DNA probe for detecting the inversions in severe haemophilia A patients. The probe shows high homology to the original probe described elsewhere as well as to the relevant DNA sequence in the intron 22. of the Factor VIII gene. No cross-hybridisation between the probe and DNA of nonhuman origin was detected.
American journal of medical genetics, Jun 3, 2003
Here we report a boy with dilated cardiomyopathy and severe Duchenne muscular dystrophy (DMD). Th... more Here we report a boy with dilated cardiomyopathy and severe Duchenne muscular dystrophy (DMD). The disease-causing mutation was a new 16 bp deletion in exon 44 of the dystrophin gene, which led to frameshifting and premature translation termination. This deletion in exon 44 was associated with dilated cardiomyopathy. The dystrophin region in exon 44 might be considered as one of the high-risk regions in which mutations could lead to myocardial damage, dilated cardiomyopathy, and early death. The abundance of repeated motifs was detected within the deleted segment and in the region. These sequence motifs might be involved in secondary structure formation and thus they could participate in the mutation generation.
BMC Hematology, Mar 18, 2004
Background: Haemophilias are the most common hereditary severe disorders of blood clotting. In fa... more Background: Haemophilias are the most common hereditary severe disorders of blood clotting. In families afflicted with heamophilia, genetic analysis provides opportunities to prevent recurrence of the disease. This study establishes a diagnostical strategy for carriership determination and prenatal diagnostics of haemophilia A in Bulgarian haemophilic population. Methods: A diagnostical strategy consisting of screening for most common mutations in the factor VIII gene and analysis of a panel of eight linked to the factor VIII gene locus polymorphisms was established. Results: Polymorphic analysis for carrier status determination of haemophilia A was successful in 30 families out of 32 (94%). Carrier status was determined in 25 of a total of 28 women at risk (89%). Fourteen prenatal diagnoses in women at high risk of having a haemophilia A-affected child were performed, resulting in 6 healthy boys and 5 girls. Conclusion: The compound approach proves to be a highly informative and cost-effective strategy for prevention of recurrence of haemophilia A in Bulgaria. DNA analysis facilitates carriership determination and subsequent prenatal diagnosis in the majority of Bulgarian families affected by haemophilia A.
PubMed, Jul 1, 2009
(Full text is available at http://www.manu.edu.mk/prilozi). This is a family of three children, b... more (Full text is available at http://www.manu.edu.mk/prilozi). This is a family of three children, born to healthy Macedonian parents after uneventful pregnancies and delivery. The index child was an eight-year-old girl admitted for abdominal discomfort and distension: the spleen was 14cm below the costal margin (BCM), the liver 8cm BCM. No bone pain or pathology was reported. There was mild pancytopaenia (hemoglobin 11.2 gm/L; WBC counts 4.6 x 10;3; platelets 70 x 10;3). Liver function tests, renal ultrasound, bone scan, and a chest radiograph were within normal limits. Bone marrow analysis in this child and her two brothers (11 and 6.5 years old) revealed Gaucher cells. Both brothers had only mild anaemia, but the older brother had been splenectomized prior to diagnosis of GD1. Enzyme analysis revealed low activity (2.59, 1.62, and 2.55 nmol/h/mg protein, respectively); plasma chitotriosidase levels were also elevated. Genetic testing revealed homozygosity for the N370S/N370S mutation in all three siblings. In the absence of available enzyme replacement treatment (ERT), the girl was splenectomized. Removing an important immune organ (the spleen) introduces further risk for the patients. In addition, this does not solve the bone involvement characteristic for GD. ERT should be introduced for all GD1 patients in Macedonia. Key words: Gaucher disease, N370S mutation, siblings, enzyme replacement therapy.
Public Health Genomics, 2002
Akusherstvo i ginekologii͡a, 2010
PAPP-A is one of the 2 biochemical markers of the first trimester Down syndrome serum screening. ... more PAPP-A is one of the 2 biochemical markers of the first trimester Down syndrome serum screening. In Bulgaria this screening was first performed in 2006. The threshold values for evaluation of the risk of development of preeclampsia used by the researchers vary in a wide range. Nevertheless in the last several years the most used value is 0.4 MoM. The aim of represented study is evaluate the low PAPP-A levels as a marker for development of preeclampsia alone, or in combination with some risk factors. The data of 194 singleton pregnancies that underwent a first trimester Down syndrome screening between January 2008 and June 2009 had been analyzed. Twenty three patients (11.6%) developed preeclampsia, of which 8 required delivery before 34th gw. The control group includes 134 women who had term deliveries of healthy babies. Nine out of 23 (39%) patients with preeclampsia, 5 out of 8 (62.5%) patients with early onset preeclampsia and 42 out of 134 (30.4%) controls had PAPP-A levels belo...
International Journal on Disability and Human Development, 2001
International Urology and Nephrology, 1980
In this work the alterations of some acrosomal enzymes and ~,-GT were studied in diseases of the ... more In this work the alterations of some acrosomal enzymes and ~,-GT were studied in diseases of the male genital tract. Thirty-two patients with vascular diseases, seven with inflammatory diseases and twenty-four controls were investigated. In all patients the sperm morphology was studied and the following enzymes were assayed: beta-glucuronidase, beta-galactosidase, beta-glucosidase and y-GT. In all patients with vascular and inflammatory diseases we found severe hypokinesis and decreased number of spermatozoa. The activity of all four enzymes in both pathological groups was decreased in comparison with the controls, and this decrease was significant for all enzymes in males with vascular diseases and for beta-galactosidase and beta-glucosidase in cases with inflammatory diseases. Our data show that the decrease of spermatozoal count was accompanied by a decreased enzyme activity. The role of decreased sperm plasma enzyme activity, the decreased production of spermatozoa and quantitative changes in structure and acrosome enzyme content are discussed.
Journal of Biomarkers, Aug 2, 2015
Idiopathic scoliosis (IS) is the most common spinal disorder in children and adolescents. The cur... more Idiopathic scoliosis (IS) is the most common spinal disorder in children and adolescents. The current consensus on IS maintains that it has a multifactorial etiology with genetic predisposition factors. In the present study the association of two functional polymorphisms of leptin (rs7799039) and BMP4 (rs4898820) with susceptibility to IS and curve severity was investigated in a Bulgarian population sample. The molecular detection of the genotypes was performed by amplification followed by restriction technology. The statistical analysis was performed by Pearson's chi-squared test. This case-control study revealed no statistically significant association between the functional polymorphisms of leptin and BMP4 and susceptibility to IS or curve progression (> 0.05). On the basis of these results the examined polymorphic variants of leptin and BMP4 could not be considered as genetic variants with predisposition effect or as risk factors for the progression of the curve. In addition, these results do not exclude a synergistic effect of the promoter polymorphisms of leptin and BMP4 in the etiology and pathogenesis of IS. The identification of molecular markers for IS could be useful for early detection and prognosis of the risk for a rapid progression of the curve. That would permit early stage treatment of the patient with the least invasive procedures.
International Journal of Colorectal Disease, Jun 21, 2006
Objective: We studied the significance of BsmI restriction enzyme polymorphism of the vitamin D r... more Objective: We studied the significance of BsmI restriction enzyme polymorphism of the vitamin D receptor (VDR) gene and the XbaI and PvuII polymorphisms of the estrogen receptor (ER) gene in patients with type 2 diabetes n 49Y android type obesity with normal carbohydrate metabolism n 29 and healthy controls n 138X Methods: The distribution of genotypes in the study groups, as well as their relationship to fasting and 1 h postprandial serum C-peptide levels were analyzed. Results: Postprandial serum C-peptide levels of BB genotypes were significantly higher in the diabetes and obese groups 6X18 ^5X09 ngaml compared with other genotypes 2X71 ^2X45 vs. 1X72 1X97 ngamlY respectively, P 0X05X Among patients with type 2 diabetes and obese subjects, the XX allelic variant of the ER gene was more frequent P 0X00015X Postprandial C-peptide levels of subjects exhibiting XX genotype were significantly lower compared with those with Xx genotype 1X67 ^2X16 vs. 3X8 ^3X72 ngamlY P 0X021X The BBXx allelic combination of the VDR/ER receptor genes was less frequent in diabetic patients than in healthy subjects or in obese patients. The BBXx genotype was associated with significantly elevated postprandial C-peptide levels in all subjects compared with other combinations 9X65 ^3X14 vs. 1X35 ^2X82 ngamlY P 0X003X No difference was found in the distribution of the PvuII polymorphism of the ER gene or in the association with the C-peptide levels among study groups. Conclusion: Polymorphisms of the VDR/ER receptor genes might play a role in the pathogenesis of type 2 diabetes by influencing the secretory capacity of b-cells.
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Papers by Ivo M Kremensky