BARTH SYNDROME IN MALE AND FEMALE SIBLINGS CAUSED BY A NOVEL MUTATION IN THE TAZ GENE

Barth syndrome (BTHS) is an X-linked recessive disease caused by mutations in tafazzin gene (TAZ) which lead to cardiolipin deficiency and mitochondrial dysfunction. Male patients have variable clinical findings, including cardiomyopathy, skeletal myopathy, prepubertal short stature, neutropenia and 3-methylglutaconic aciduria. Female carriers are usually asymptomatic. We report a novel TAZ gene mutation in male and female siblings with left ventricular noncompaction and hypotonia. Additionally, the brother presented an intermittent neutropenia and increased urinary levels of 3-methylglutaconic and 3-methylglutaric acid. The molecular genetic testing showed that both siblings carry the mutation: c.253insC, p.(Arg85Profs*54) in exon 3 of the TAZ gene. This article presents the first case of BTHS in a heterozygous female patient with normal karyotype.

Founder p.Arg 446* mutation in the PDHX gene explains over half of cases with congenital lactic acidosis in Roma children

Investigation of 31 of Roma patients with congenital lactic acidosis (CLA) from Bulgaria identified homozygosity for the R446* mutation in the PDHX gene as the most common cause of the disorder in this ethnic group. It accounted for around 60% of patients in the study and over 25% of all CLA cases referred to the National Genetic Laboratory in Bulgaria. The detection of a homozygous patient from Hungary and carriers among population controls from Romania and Slovakia suggests a wide spread of the mutation in the European Roma population. The clinical phenotype of the twenty R446* homozygotes was relatively homogeneous, with lactic acidosis crisis in the first days or months of life as the most common initial presentation (15/20 patients) and delayed psychomotor development and/or seizures in infancy as the leading manifestations in a smaller group (5/20 patients). The subsequent clinical picture was dominated by impaired physical growth and a very consistent pattern of static cerebral palsy-like encephalopathy with spasticity and severe to profound mental retardation seen in over 80% of cases. Most patients had a positive family history. We propose testing for the R446* mutation in PDHX as a rapid first screening in Roma infants with metabolic acidosis. It will facilitate and accelerate diagnosis in a large proportion of cases, allow early rehabilitation to alleviate the chronic clinical course, and prevent further affected births in high-risk families.

First Bulgarian case of citrin deficiency caused by one novel and one recurrent mutation in the SLC25A13 gene

Citrin deficiency is an autosomal recessive disorder caused by mutations in the SLC25A13 gene and has three phenotypes: neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) in newborns, failure to thrive and dyslipidemia caused by citrin deficiency (FTTDCD) in older children, and recurrent hyperammonemia with neuropsychiatric symptoms in citrullinemia type II (CTLN2) in adults. NICCD presents in the first few weeks of life with cholestatic hepatitis syndrome, multiple aminoacidemia and hypergalactosemia. To date almost all reported patients were from East Asia and only few cases from Caucasian origin have been described. We report the first Bulgarian case of NICCD. Mutation screening of the SLC25A13 gene revealed the compound heterozygous mutations c.1081C>T (p.R361*) and c.74C>A (p. A25E) which confirmed the diagnosis of NICCD. The nonsense mutation c.1081C>T (p.R361*) is novel.

[Structure and function of pelagic zooplankton in various types of lakes (using the example of small lakes in northwestern Russia]

Changes of structure and functioning of pelagic zooplankton under lake eutrophication were studied in a group of small (without outlet) lakes in southern Karelia and Leningrad region. The lakes were morphologically similar and located within the same climatic zone. Differences in their trophic status were connected with anthropogenic eutrophication. Correlation between species number and feeding resources of a lake is determined as: Y = (8.01 +/- 3.85) + (0.29 +/- 0.07)X1 + (6.75 +/- 1.52)X2, r2 = 0.95, (1) Y--number of zooplankton species, X1--average chlorophyll concentration for the season, mg/1; X2--average value of biochemical oxygen demand (expressed in mgC/1). Average biomass of zooplankton for season also depends on food: logY = (-0.054 +/- 0.224) + (0.242 +/- 0.094)logX1 + (0.170 +/- 0.179)logX2, n = 13, r2 = 0.87, (2) Y--average zooplankton biomass for the season, kcal/m3, X1 and X2 the same as (1). Increase in species number and zooplankton bimass determined primarily by Rotatoria occur in parallel to chlorophyll concentration and activity of bacteria. In acid lakes rotifers are not important in energy balance. In mezotrophic lakes two main energy paths are formed--through rotifers and through Crustacea. The role of rotifers is extremely important in eutrophic lakes where about 80% of energy paths through them. The ratio community production to energy consumption for the growing season is also depended on the community structure (species number, equitability, connectence): Y = (2.257 +/- 0.026) - (0.368 +/- 0.031)X1 + (5.160 +/- 0.442)X2, r2 = 0.99, (3) Y--average seasonal production of zooplankton, kcal/m2; X1--maximal meaning of Shannon index (bites), calculated on biomass value; X2--connectence of the community, calculated according Briand (1983). Eutrophication changes the stability of lakes relative to external influences, while low productive lakes are very sensitive to the increase in nutrient load, high productive lakes are more influenced by changes in fish predation.

[Characteristics of circulation, ventilation and gas exchange in intact and anesthetized dogs]

Light hexenal anesthesia was found not to affect the mean values of hemodynamics and O2 tension in the blood but increased the CO2 tension in arterial blood and decreased the oxyhemoglobin content and pH of the blood in dogs.