Two novel mutations in seven Czech and Slovak kindreds with familial neurohypophyseal diabetes insipidus-benefit of genetic testing.

UNLABELLED: Familial neurohypophyseal diabetes insipidus (FNDI) is a rare hereditary disorder with unknown prevalence characterized by arginine-vasopressin hormone (AVP) deficiency resulting in polyuria and polydipsia from early childhood. We report the clinical manifestation and genetic test results in seven unrelated kindreds of Czech or Slovak origin with FNDI phenotype. The age of the sign outset ranged from 2 to 17 years with remarkable interfamilial and intrafamilial variability. Inconclusive result of the fluid deprivation test in three children aged 7 and 17 years old might cause misdiagnosis; however, the AVP gene analysis confirmed the FNDI. The seven families segregated together five different mutations, two of them were novel (c.164C > A, c.298G > C). In addition, DNA analysis proved mutation carrier status in one asymptomatic 1-year-old infant. CONCLUSIONS: The present study together with previously published data identified 38 individuals with FNDI in the studied population of 16 million which predicts a disease prevalence of 1:450,000 for the Central European region. The paper underscores that diagnostic water deprivation test may be inconclusive in polyuric children with partial diabetes insipidus and points to the clinical importance and feasibility of molecular genetic testing for AVP gene mutations in the proband and her/his first degree relatives. WHAT IS KNOWN: • At least 70 different mutations were reported to date in about 100 families with neurohypophyseal diabetes insipidus (FNDI), and new mutations appear sporadically. What is New: • Two novel mutations of the AVP gene are reported • The importance of molecular testing in children with polyuria and inconclusive water deprivation test is emphasized.

High Incidence of Heterozygous ABCC8 and HNF1A Mutations in Czech Patients With Congenital Hyperinsulinism.

CONTEXT: Congenital hyperinsulinism of infancy (CHI) represents a group of heterogeneous disorders characterized by oversecretion of insulin from pancreatic ß-cells causing severe hypoglycemia. OBJECTIVE: We studied the distribution of genetic causes of CHI in a Czech population. METHODS: Countrywide collection of patients with CHI included 40 subjects (12 females, median age of diagnosis, 1 wk [interquartile range, 1-612 wk]). We sequenced the ABCC8, KCNJ11, GLUD1, GCK, HADH, UCP2, SLC16A1, HNF4A, and HNF1A genes and investigated structural changes in the ABCC8 gene. We functionally tested novel variants in the ABCC8 gene by Rb(86+) efflux assay and novel variants in the HNF1A gene by transcriptional activation and DNA-binding tests. RESULTS: We found causal mutations in 20 subjects (50%): 19 carried a heterozygous mutation while one patient was homozygous for mutation in the ABCC8 gene. Specifically, we detected 11 mutations (seven novel) in ABCC8, one novel mutation in KCNJ11, five mutations (two novel) in HNF1A, two novel mutations in HNF4A, and one in GCK. We showed a decrease of activation by diazoxide in mutant KATP channels with novel ABCC8 variants by 41-91% (median, 82%) compared with wild-type (WT) channels and reduced transcriptional activity of mutant HNF1A proteins (2.9% for p.Asn62Lysfs93* and 22% for p.Leu254Gln) accompanied by no DNA-binding ability compared with WT HNF1A. CONCLUSION: We detected a higher proportion of heterozygous mutations causing CHI compared with other cohorts probably due to lack of consanguinity and inclusion of milder CHI forms. Interestingly, HNF1A gene mutations represented the second most frequent genetic cause of CHI in the Czech Republic. Based on our results we present a genetic testing strategy specific for similar populations.

Diseases caused by defects of energy level and loss of coherence in living cells.

Human and animal diseases are brought about by pathological alterations of production, composition, and conformation of macromolecules and structures in cells. Additional contributing factors include changes in physiological states caused by disturbances of energy supply, energy transduction, energy dissipation in moving or oscillating parts, and parasitic energy consumption. Disturbances of energy states may endanger existence of the system. The cell-mediated immunity (CMI) response of T lymphocytes correlating with their adherence properties was examined using antigen prepared from the serum of inbred laboratory mice strain C3H H(2k) infected with lactate dehydrogenase elevating (LDH) virus. LDH virus is a parasite on the cellular energy system. Significant CMI response was elicited in T lymphocytes prepared from the blood of patients with cancer of different phenotypes, acute myocardial infarctions, schizophrenia, and recurrent spontaneous abortions in early pregnancy from unknown reasons. The CMI response is assumed to monitor transferred information about decreased levels of energy states and decoherence in the cells caused by mitochondrial malfunction, parasitic consumption, production of lactate, and possibly other disturbances. The LDH virus infection or similar pathological processes caused by different agents might be connected with the diseases and monitored by the examined CMI response. A large amount of mitoses with chromosome defects in aborted fetuses suggest increased mutability of genomes caused by defective energy states.

Isoelectric Focusing of Serum Apolipoprotein C-III as a Sensitive Screening Method for the Detection of O-glycosylation Disturbances.

Apolipoprotein C-III (ApoC-III) is a glycoprotein carrying the most common O-linked glycan structure and is abundantly present in serum, what renders it a suitable marker for analysis of O-glycosylation abnormalities. Isoelectric focusing followed by a Western blot of ApoC-III, using PhastSystem™ Electrophoresis System (GE Healthcare), was introduced as a rather simple and rapid method for screening of certain subtypes of inherited glycosylation disorders. The study's aim was to establish this method in our laboratory, what included performing the analysis in a group of 170 healthy individuals to set the reference range of detected relative amounts of sialylated ApoC-III isoforms and to evaluate the gender- and age-dependent differences. A significant relative increase of asialo-ApoC-III with growing age was found. Secondly, we examined serum from patients with selected metabolic disorders and detected minor O-glycosylation changes in diseases such as Prader-Willi syndrome, PGM1 (phosphoglucomutase 1) or MAN1B (class 1B alpha-1,2-mannosidase) deficiency. Our results show that this method allows for a sensitive detection of ApoC-III O-glycosylation status, however this might be modulated by several factors (i.e. nutrition, medication) whose exact role remains to be determined.

Post-natal growth of 157 children born as extremely premature neonates.

AIM: With increasing survival rate of extremely premature neonates, their long-term outcomes including growth and risk factors for later disorders need to be considered. We prospectively evaluated anthropometric parameters in children born as extremely premature neonates. METHODS: Anthropometric parameters were measured at the ages of 2 and 5 years in 72 extremely premature children born between the 22nd and 25 + 6th weeks of gestation (group I) and 85 children born between the 26th and 27 + 6th weeks of gestation (group II). RESULTS: Although catch-up in the postnatal growth was observed in both groups of children, resulting in growth improvement, the height of the extremely premature children at the ages of 2 and 5 years remains lower (P < 0.01) compared with the control population. A decline in head growth was observed in both groups between the ages of 2 and 5 years, resulting in decrease of standard deviation score (SDS) for head circumference (HC) in comparison with that of the control population, accompanied by an increased number of children with microcephaly, defined as HC < -2 SD. At the age of five, microcephaly was found in 18% of children from group I and 11.7% of children from group II. At the age of 5 years, the waist and hip circumferences and ten skinfolds were not different between both groups of children. CONCLUSION: Long-term follow-up of extremely premature neonates is important not only to establish their growth patterns but also for risk factors assessment including adiposity for later development of adult-onset diseases.

Cytosine-Adenosine (CA)n repeats polymorphism in IGF-I gene and early growth in infants born appropriate and small for gestational age.

BACKGROUND: IGF-I gene polymorphisms might alter IGF-I level resulting in decreased foetal and postnatal growth and increased risk for diabetes mellitus type 2 and cardiovascular diseases in adulthood. OBJECTIVES: We analyzed the association between Cytosine-Adenosine (CA)10-24 repeats polymorphism in promoter region of the IGF-I gene and early growth in infants with birth weight appropriate for gestational age (AGA) and small for gestational age (SGA). DESIGN AND METHODS: All neonates were born at term, 196 of them were AGA and 26 SGA. Blood for DNA analyses was obtained from placental part of umbilical vein. Genotyping was performed using fragment analyses of IGF-I gene promoter region. The data about postnatal growth in the group of AGA children were obtained at the age of 18 months, in SGA children at 12 months. RESULTS: No differences in the frequency of wild type allele with (CA)19 repeats and polymorphisms with (CA)<19 or (CA)>19 repeats were observed between AGA and SGA children. The average birth weight and length in AGA wild type (CA)19 homozygotes were lower in comparison with AGA carriers of various (CA)n polymorphisms but all observed anthropometric differences disappeared at the age of 18 months. In SGA children, no differences were found between number of (CA)n repeats and anthropometric parameters both at birth and at the age of 12 months. CONCLUSIONS: Although (CA)n repeats polymorphism in IGF-I gene might affect prenatal growth in AGA children, our results have not shown any impact of variable number of (CA) n repeats in IGF-I gene on postnatal growth.