Genotype-phenotype correlation in 44 Czech, Slovak, Croatian and Serbian patients with mucopolysaccharidosis type II.

Mucopolysaccharidosis type II (Hunter syndrome, MPS II, OMIM 309900) is an X-linked lysosomal storage disorder caused by deficiency of iduronate-2-sulfatase (IDS). We analyzed clinical and laboratory data from 44 Slavic patients with this disease. In total, 21 Czech, 7 Slovak, 9 Croatian and 7 Serbian patients (43 M/1 F) were included in the study (median age 11.0 years, range 1.2-43 years). Birth prevalence ranged from 1:69,223 (Serbia) to 1:192,626 (Czech Rep.). In the majority of patients (71%), the disease manifested in infancy. Cognitive functions were normal in 10 patients. Four, six and 24 patients had mild, moderate, and severe developmental delay, respectively, typically subsequent to developmental regression (59%). Residual enzyme activity showed no predictive value, and estimation of glycosaminoglycans (GAGs) had only limited importance for prognosis. Mutation analysis performed in 36 families led to the identification of 12 novel mutations, eight of which were small deletions/insertions. Large deletions/rearrangements and all but one small deletion/insertion led to a severe phenotype. This genotype-phenotype correlation was also identified in six cases with recurrent missense mutations. Based on patient genotype, the severity of the disease may be predicted with high probability in approximately half of MPS II patients.

New Mutations Associated with Rasopathies in a Central European Population and Genotype-Phenotype Correlations.

We performed the genetic analysis of Rasopathy syndromes in patients from Central European by direct sequencing followed by next generation sequencing of genes associated with Rasopathies. All 51 patients harboured the typical features of Rasopathy syndromes. Thirty-five mutations were identified in the examined patients (22 in PTPN11, two in SOS1, one in RIT1, one in SHOC2, two in HRAS, three in BRAF, two in MAP2K1 and two in the NF1 gene). Two of them (p.Gly392Glu in the BRAF gene and p.Gln164Lys in the MAP2K1 gene) were novel with a potentially pathogenic effect on the structure of these proteins. Statistically significant differences in the presence of pulmonary stenosis (63.64% vs. 23.81%, P = 0.013897) and cryptorchidism (76.47% vs. 30%, P = 0.040224) were identified as the result of comparison of the prevalence of phenotypic features in patients with the phenotype of Noonan syndrome and mutation in the PTPN11 gene, with the prevalence of the same features in patients without PTPN11 mutation. Cryptorchidism as a statistically significant feature in our patients with PTPN11 mutation was not reported as significant in other European countries (Germany, Italy and Greece). The majority of mutations were clustered in exons 3 (45.45%), 8 (22.73%), and 13 (22.73%) of the PTPN11 gene.

Late onset form of Pompe disease.

BACKGROUND: Pompe disease is an autosomal recessive disorder of glycogen metabolism caused by deficiency in lysosomal enzyme α-glucosidase. OBJECTIVES: We present first two patients from Slovakia with confirmed Pompe disease. METHODS: Activity of α-glucosidase was measured using 4-methylumbelliferyl-α-D-glucopyranoside with the presence of acarbose, inhibitor that eliminates isoenzyme interference of maltase-glucoamylase. This methodical approach is substantial for determination of lysosomal enzyme deficiency. Using molecular genetic methods, PCR-RFLP and direct sequencing of coding region α-glucosidase gene (GAA) we have identified causal mutations in our patients. RESULTS: Late-onset type of disease was confirmed by measuring α-glucosidase activity in leukocytes isolated from blood. The presence of common Caucasian mutation c.-32-13T>G was proved by genetic testing in the first patient in homozygous state. Second patient was a compound heterozygote, with mutation c.-32-13T>G on one allele and mutation A486P on the second allele. CONCLUSION: We present a diagnostic algorithm for diagnosing the Pompe disease in patients of European origin. Enzyme replacement therapy has been used as a treatment option for improving the quality of life of patients. Early diagnosis and treatment of Pompe disease are considered to be critical for maximum efficacy of enzyme replacement therapy (Tab. 1, Fig. 3, Ref. 20).

Increased plasma levels of the high mobility group box 1 protein (HMGB1) are associated with a higher score of gastrointestinal dysfunction in individuals with autism.

Autism is a disorder of neural development characterized by impairments in communication, social interaction, restricted interests and repetitive behavior. The etiology of autism is poorly understood, the evidence indicates that inflammation may play a key role. In autism a high prevalence of gastrointestinal disturbances is reported, that are linked to a low-grade chronic inflammation of the intestinal mucosa. High mobility group box 1 protein (HMGB1) is an intranuclear protein that can be passively released from necrotic cells or actively secreted under inflammatory conditions as alarmin or late proinflammatory cytokine. The objective of this study was to measure plasma levels of HMGB1 in individuals with autism and to analyze their association with gastrointestinal symptoms. The study involved 31 subjects with low-functioning autistic disorder aged 2-22 years and 16 healthy controls. Plasma HMGB1 levels were significantly higher in individuals with autism than in controls (13.8+/-11.7 ng/ml vs. 7.90+/-4.0 ng/ml, p<0.02). In subjects with plasma HMGB1 levels higher than 11 ng/ml severe forms of GI disorders were more prevalent (83.3 %) than in subjects with lower levels (38.9 %, p<0.04). Results of the study support the involvement of the systemic low-grade inflammation in the pathomechanisms of autism and its possible association with GI symptoms.

Rasopathies - dysmorphic syndromes with short stature and risk of malignancy.

OBJECTIVES: The term ´Rasopathies´ represents a group of five neurodevelopmental syndromes (Noonan, LEOPARD, Costello, Cardio-facio-cutaneous, and Neurofibromatose-Noonan syndrome) caused by germline mutation in genes encoding proteins involved in RAS/MAPK (rat sarcoma/mitogen-activated protein kinase) signaling pathway. The RAS/MAPK signaling pathway participates in regulation of cell determination, proliferation, differentiation, migration, and senescence and dysregulation of this pathway can lead to the risk of tumorigenesis. In this review, we aim to summarize the current clinical and molecular genetic knowledge on Rasopathies with special attention for the risk of cancer. We propose also clinical and therapeutic approach for patients with malignancy. METHODS: We are reviewing the clinical and molecular basis of Rasopathies based on recent studies, clinical examination, and molecular diagnostics (mutation analysis of causal genes for Rasopathies) in Slovak pediatric patients. RESULTS: Some clinical features, such as short stature, a specific facial dysmorphology and cardiac abnormalities are common to all of Rasopathy syndromes. However, there are unique signs by which the syndromes can differ from each other, especially multiple lentigo in LEOPARD syndrome, increased risk of malignancy in Costello syndrome, dry hyperkeratotic skin in patients with cardio-facio-cutaneous syndrome, and neurofibromas and cafe-au-lait spots in neurofibromatosis-Noonan syndrome. CONCLUSION: Despite the overlapping clinical features, Rasopathy syndromes exhibit unique fenotypical features and the precise molecular diagnostics may lead to confirmation of each syndrome. The molecular diagnostics may allow the detection of pathogenic mutation associated with tumorigenesis.

Clustering of mutations in the 5' tertile of the NF1 gene in Slovakia patients with optic pathway glioma.

Optic pathway gliomas (OPG) occur in 15% of patients with neurofibromatosis type 1 (NF1; OMIM 162200). Genotype-phenotype correlations in patients with NF1 may help to determine the risk group for developing complications such as OPG in coincidence with other NF1.features. We evaluated 52 patients with NF1 (25 with OPG and 27 without OPG). All subjects underwent a clinical examination focused on neurofibromatosis type 1 and molecular diagnostics of NF1 gene using protocol based on RNA analysis confirming the diagnosis of NF1. In the group with OPG patients, there was a significantly higher incidence of freckling (P=0.017), neurofibromatosis bright objects (NBO) (P=0.0038), compared to the group without OPG. The differences between the groups with respect to Lisch nodules were on the borderline of statistical significance (P=0.088). The frequency of neurofibromas in the group with OPG was not significant (P=0.9). From all patients with the mutation localized in the first tertile of the NF1 gene majority (71%) had optic glioma compared to individuals who didn't have the OPG 29% (P=0.0049). Our results present the clustering of mutations in the 5'tertile of NF1 gene in patients with optic nerve glioma and suggest higher incidence of freckling and neurofibromatosis brain objects in these patients. Molecular analysis of NF1 gene is important part in complex management of NF1 patients and contributes to a better understanding of clinical picture of NF1 patients. .

Ratio of lipid parameters to coenzyme Q10 could be used as biomarker of the development of early complications of obesity in children.

BACKGROUND: Chronic obesity is associated with reduced levels of antioxidants, increased free oxygen radicals, and oxidative stress. Child obesity may lead to the development of complications, such as changes in metabolism, metabolic syndrome, neurological, cardiological, respiratory, renal, gastrointestinal, endocrinological, and musculoskeletal conditions. The aim of the present study is to establish whether there is a correlation between basal CoQ10 plasma concentration and the ratio of lipid parameters to CoQ10 in obese children. METHODS: The study included 101 obese children and 20 non-obese children, aged 10-18 years. Antioxidants - CoQ10-OX, α-tocopherol, ß-carotene - in plasma were measured by HPLC method with UV detector, and plasma malondialdehyde spectrophotometrically. RESULTS: High correlation was found between plasma concentration of CoQ10 and the ratio of total Chol/CoQ10-OX as well as between CoQ10-OX and the ratio of HDL Chol/CoQ10 in plasma of obese children. The lowest correlation was between plasma concentration of CoQ10-OX and the ratio of LDL Chol/CoQ10 , as well as between CoQ10-OX and the ratio of TAG/CoQ10 in obese children. CONCLUSION: An increase of the ratios of lipid parameters to CoQ10 is associated with child obesity and could be used as biomarkers of early complications in the development of obesity in children (Tab. 3, Fig. 5, Ref. 22).

Problems of metabolic syndrome diagnostics in children.

OBJECTIVE: Increasing prevalence of exogenous obesity in children appears possibly related to changes in their lipid and carbohydrate metabolism resulting from insulin resistance which, together with obesity and arterial hypertension, are among the components of metabolic syndrome. The aim of this study was to evaluate the age related incidence of obesity complications and the prevalence of metabolic syndrome in children according to the latest criteria. METHODS: A total of 98 obese children were divided in two age groups (5 to 10 and 10 to 16 years). In all patients the BMI was calculated, standard deviation score of BMI (SDS BMI) was estimated according to the data by anthropometric surveys Slovakia and obesity was defined as SDS BMI >2 which is equal to 97th percentile for the appropriate age and gender. Blood pressure >95th percentile for the appropriate gender, age and body was classified as hypertension. Fasting glycemia, total and HDL cholesterol and triglycerides were determined in serum and oral glucose tolerance test was performed. Insulin resistance was classified according to HOMA index. RESULTS: Among 21 children less than 10 years of age lower HOMA values and no impaired glucose tolerance appeared, but hypercholesterolemia was found in 8 cases (38.1 %). Among 77 patients aged 10 to 16 years increased frequency of cases was found with insulin resistance (37.7 %), increased triglycerides (53.3 %), decreased HDL cholesterol (54.4 %) and impaired glucose tolerance (7.8 %). In this group 32.5 % of children showed metabolic syndrome based on modified IDF criteria, while such prevalence rose to 39.0 % if borderline criteria for blood pressure were used. CONCLUSION: The treatment of referred pathological states requires lifestyle changes and follow up at the specialized clinic.

Assay design and optimization of mutant-enriched PCR based method for detection of K-ras gene mutations in pancreatic carcinoma.

The aim of our work was to develop a fast, reliable and sensitive PCR method to detect K-ras mutations in various clinical samples. There is a need for an unimpeachable method for early diagnosis and/or screening of pancreatic cancer (PC). We optimized and subsequently analyzed four methods based on mutant-enriched PCR for the sensitivity, cost and time expense. Using the selected optimal method we examined codon 12 K- ras mutations in a study population of 59 patients with upper GIT malignancies. Reliability of the genotyping was confirmed by sequencing. By using the best of our modified mutant-enriched PCR methods we achieved sensitivity of 1:1 x 10(5). Further studies are necessary to determine the optimal biological material sampling in PC.

[Variation in manifestations of heteroplasmic mtDNA mutation 8993 T>G in two families]. / Rozmanitost projevu heteroplazmické mtDNA mutace 8993 T > G ve dvou rodinách.

BACKGROUND: The most frequent manifestations of heteroplasmic mitochondrial DNA (mtDNA) mutation 8993 T > G are Leigh syndrome or NARP syndrome (Neurogenic Muscle Weakness, Ataxia, and Retinitis Pigmentosa). The authors describe heterogeneity of clinical symptoms and results of biochemical and molecular analyses in seven severely clinically affected children from two unrelated families with heteroplasmic mtDNA mutation 8993 T > G. METHODS AND RESULTS: Seven clinically affected children from two unrelated families were born in term after an uneventful pregnancy. The failure to thrive, psychomotor retardation, hypotonic or spastic quadruparesis, hypertrophic cardiomyopathy, hepatopathy and hyperlactacidaemia developed after birth. Five children died in the first year of life during acute respiratory infection, one girl died at the age of 3 months with sudden death syndrome, only one boy with spastic quadruparesis and severe psychomotor retardation survived to the age of 8 years. Molecular analyses in all investigated children and their clinically non-affected mothers revealed the presence of heteroplasmic mtDNA mutation 8993 T > G. Mutated copies of mtDNA molecules in maternal tissues were in the range of 15-22%. The mutation load in all analysed children's tissues was higher than 90%. CONCLUSIONS: A broad spectrum of clinical symptoms may be observed in families with heteroplasmic mtDNA mutations 8993 T > G. Affected children with a mutation load higher than 90% usually do not survive after infancy. In both investigated families, a profound increase in the levels of heteroplasmy of mtDNA mutation 8993 T > G was observed in two subsequent generations.

[Peroxisomal hereditary diseases]. / Peroxizómové dedicné ochorenia.

Nearly two tens of diseases are known to be caused by impairment of several metabolic functions of peroxisomes, or by deficiency in individual peroxisomal enzymes. With the exception of X-bound adrenoleukodystrophy, all diseases are based on autosomally recessive type of inheritance and a majority of them are characteristic by specific neurologic symptoms. The group of diseases in which patients develop a generalised loss of peroxisomal functions includes: Zellweger's cerebro-hepato-renal syndrome, neonatal adrenoleukodystrophy, infantile Refsum's disease, hyperpipecolic acidaemia. Other diseases, such as rhizomelic chondrodysplasia punctata and Zellweger-like syndrome are accompanied by a deficiency in several enzymatic activities. X-bound adrenoleukodystrophy, pseudo-Zellweger's syndrome, hyperoxaluria 1, adult form of Refsum's disease and acatalasaemia are peroxisomal diseases with a deficiency of a single enzyme. In clinically most severe diseases (generalised loss of peroxisomal functions), the impairment of peroxisomal biogenesis is caused assumedly due to the defect in some of the peroxisomal membrane proteins. The biochemical findings are brought about by insufficiency in such metabolic functions as oxidation of fatty acids with very long chains, oxidation of the phytanic and pipecolic acids, synthesis of cholesterol, bile salts and plasmalogenes. Rhizomelic chondrodysplasia punctata and Zellweger's syndrome are more moderate forms which are dominantly biochemically manifestant by an impairment in the synthesis of plasmalogenes. Among the diseases characterised by a deficiency in individual peroxisomal enzymes, most frequent is the X-bound andrenoleukodystrophy which has several clinical phenotypes manifestant in childhood, as well as a clinically less severe form manifestant in adulthood-adrenomyeloneuropathy. The diagnosis of peroxisomal diseases is performed by use of a wide range of methods (morphological, biochemical, immunochemical and molecular genetic examinations) which enable both postnatal and prenatal diagnostics. (Tab. 1, Ref. 104.)