Immunologic phenotype of a child with the MEHMO syndrome.

MEHMO syndrome is a rare X-linked syndrome characterized by Mental retardation, Epilepsy, Hypogenitalism, Microcephaly, and Obesity associated with the defect of protein synthesis caused by the EIF2S3 gene mutations. We hypothesized that the defect in protein synthesis could have an impact on the immune system. We describe immunologic phenotype and possible treatment outcomes in patient with MEHMO syndrome carrying a frame-shift mutation (I465fs) in the EIF2S3 gene. The proband (currently 9-year-old boy) had normal IgG and IgM levels, but had frequent respiratory and urinary tract infections. On subcutaneous immunoglobulin therapy achieving supra-physiological IgG levels the frequency of infections significantly decreased in Poisson regression by 54.5 % (CI 33.2-89.7, p=0.017). The MEHMO patient had had frequent acute infections despite normal IgG and IgM serum levels and responded well to the immunoglobulin treatment.

Neonatal hypoglycemia, early-onset diabetes and hypopituitarism due to the mutation in EIF2S3 gene causing MEHMO syndrome.

Recently, the genetic cause of several syndromic forms of glycemia dysregulation has been described. One of them, MEHMO syndrome, is a rare X-linked syndrome recently linked to the EIF2S3 gene mutations. MEHMO is characterized by Mental retardation, Epilepsy, Hypogonadism/hypogenitalism, Microcephaly, and Obesity. Moreover, patients with MEHMO had also diabetes and endocrine phenotype, but detailed information is missing. We aimed to provide more details on the endocrine phenotype in two previously reported male probands with MEHMO carrying a frame-shift mutation (I465fs) in the EIF2S3 gene. Both probands had a neonatal hypoglycemia, early onset insulin-dependent diabetes, and hypopituitarism due to dysregulation and gradual decline of peptide hormone secretion. Based on the clinical course in our two probands and also in previously published patients, neonatal hypoglycemia followed by early-onset diabetes and hypopituitarism may be a consistent part of the MEHMO phenotype.

The molecular genetic background of familial hypercholesterolemia: data from the Slovak nation-wide survey.

Familial hypercholesterolemia (FH) is most frequently caused by LDLR or APOB mutations. Therefore, the aim of our study was to examine the genetic background of Slovak patients suspected of FH. Patients with clinical suspicion of FH (235 unrelated probands and 124 family relatives) were recruited throughout Slovakia during the years 2011-2015. The order of DNA analyses in probands was as follows: 1. APOB mutation p.Arg3527Gln by real-time PCR method, 2. direct sequencing of the LDLR gene 3. MLPA analysis of the LDLR gene. We have identified 14 probands and 2 relatives with an APOB mutation p.Arg3527Gln, and 89 probands and 75 relatives with 54 different LDLR mutations. Nine of LDLR mutations were novel (i.e. p.Asp90Glu, c.314-2A>G, p.Asp136Tyr, p.Ser177Pro, p.Lys225_Glu228delinsCysLys, p.Gly478Glu, p.Gly675Trpfs*42, p.Leu680Pro, p.Thr832Argfs*3). This is the first study on molecular genetics of FH in Slovakia encompassing the analysis of whole LDLR gene. Genetic etiology of FH was confirmed in 103 probands (43.8 %). Out of them, 86.4 % of probands carried the LDLR gene mutation and remaining 13.6 % probands carried the p.Arg3527Gln APOB mutation.

Age of obesity onset in MC4R mutation carriers.

OBJECTIVES: The mutations in gene for the melanocortin-4 receptor (MC4R) are the most common etiology factors of monogenic obesity development. Recently, it has been shown that current life style has a significant impact on the phenotype of MC4R mutation carriers - increases the penetrance of the mutations. We aimed to study the impact of the current age on the time of obesity onset among MC4R mutation carriers. METHODS: DNA analysis of the MC4R gene was performed in 268 unrelated Slovak and Moravian obese children and adolescents 18 years and 28 blood relatives >18 years of the probands with a mutation. RESULTS: Three different previously described heterozygous loss of function MC4R mutations (p.Ser19Alafs*34, p.Ser127Leu, and p.Gly181Asp) were found in 3 <18 years probands, 3 adult probands, and 6 adult obese/overweight family relatives. The age of obesity onset in mutation carriers was 1 year in all probands in the children group and 1-35 years (median 11 years) in adults. The age of the obesity onset significantly correlated (R=0.809, p=0.028) with the current age in all of the MC4R mutation carriers. CONCLUSIONS: The age of obesity onset in the present child generation of MC4R mutation carriers is decreasing compared to the age of onset in their parents' generation. This is in agreement with similarly increasing penetrance of obesity in MC4R mutation carriers and it points out to escalation of obesogenic potential of environment.

Molecular-genetic aspects of familial hypercholesterolemia.

Familial hypercholesterolemia (FH) is the world's most abundant and the most common heritable disorder of lipid metabolism. The prevalence of the disease in general population is 1:500. Therefore the approximate number of FH patients all over the world is 14 million. From the genetic point of view the disease originates as a result of mutations in genes affecting the processing of LDL particles from circulation, resulting in an increase in LDL cholesterol and hence total cholesterol. These are mutations in genes encoding LDL receptor, apolipoprotein B, proprotein convertase subtilisin/kexin 9 and LDL receptor adaptor protein 1. Cholesterol depositing in tissues and blood vessels of individuals creates tendon xanthoma, xanthelesma and arcus lipoides cornae. Due to the increased deposition of cholesterol in blood vessels, atherosclerosis process is accelerated, what leads to a significantly higher risk of premature cardiovascular diseases. Therefore, early clinical diagnosis confirmed by the DNA analysis, and effective treatment are crucial to reduce the mortality and high risk of premature atherosclerotic complications.

Melanocortin-4 receptor gene mutations in obese Slovak children.

The most common etiology of non-syndromic monogenic obesity are mutations in gene for the Melanocortin-4 receptor (MC485) with variable prevalence in different countries (1.2-6.3 % of obese children). The aim of our study was 1) to search for MC4R mutations in obese children in Slovakia and compare their prevalence with other European countries, and 2) to describe the phenotype of the mutation carriers. DNA analysis by direct Sanger sequencing of the coding exons and intron/exon boundaries of the MC4R gene was performed in 268 unrelated Slovak children and adolescents with body mass index above the 97(th) percentile for age and sex and obesity onset up to 11 years (mean 4.3+/-2.8 years). Two different previously described heterozygous loss of function MC4R variants (i.e. p.Ser19Alafs*34, p.Ser127Leu) were identified in two obese probands, and one obese (p.Ser19Alafs*34), and one lean (p.Ser127Leu) adult family relatives. No loss of function variants were found in lean controls. The prevalence of loss-of-function MC4R variants in obese Slovak children was 0.7 %, what is one of the lowest frequencies in Europe.

Impact of Type 2 diabetes on Glucokinase diabetes (GCK-MODY) phenotype in a Roma (Gypsy) family - case report.

OBJECTIVES: Glucokinase (GCK) diabetes is a mild form of the monogenic diabetes characterized by the fasting hyperglycemia without signs of metabolic syndrome and very low risk for chronic complications of diabetes. For the Type 2 diabetes (T2D), signs of the metabolic syndrome with high risk for chronic micro- and macro-vascular complications are typical. The prevalence of the GCK-diabetes is estimated from 0.5 to 1% in the diabetic patients. The T2D is the most prevalent type of the diabetes (it encompasses more than 85% of all the diabetic patients). According to the epidemiology, the coincidence of these two diabetes subtypes may occur; nevertheless no case reports on the above mentioned two diabetes subtypes have been published. The aim of the study was: 1) to perform the DNA analysis in three brothers, two of them with the fasting hyperglycemia and one with normal glucose tolerance, and their father with T2D metabolic syndrome and 2) to study the coincidence of the GCK-diabetes with T2D and its effect on the diabetic phenotype. PATIENTS AND METHODS: We report about a Roma (Gypsy) family consisting of three brothers: 17 years old probant and two older brothers (21 and 25 years), and their father. The probant is suffering from fasting hyperglycemia. His 25 years old diabetic brother and their father suffer from obesity, hypertension, dyslipidemia, and hyperglycemia. The glucokinase gene was analyzed by direct sequencing in each of the brothers and their father, and appropriate phenotype characteristics were also carried out on each of the family members. RESULTS: In the proband and his diabetic brother with the fasting hyperglycemia, a heterozygous mutation of the glucokinase gene p.Arg36Trp was found. The proband's phenotype was consistent with the GCK-diabetes, while the diabetic brother displayed already features of the metabolic syndrome. Although, the latter one suffered from the overweight, hypertension, and elevated triglycerides, his fasting hyperglycemia (8.3 mmol/l) was still consistent with the GCK-diabetes. Their father is also a heterozygous mutation carrier of the same mutation displaying all the features of the metabolic syndrome. In his case, the fasting hyperinsulinemia (43.5 µU/ml) and fasting plasma glucose (10.4 mmol/l) are more typical for the T2D than GCK-diabetes. CONCLUSIONS: We found coincidence between the GCK-diabetes and T2D in the members of a single Roma (Gypsy) family. Since the chronic complications are rare in the GCK-diabetes, the major risk factor for the further morbidity may be in the development of the T2D. The overlapping of the GCK-diabetes with other types of diabetes, particularly the T2D, makes the diagnostics difficult and therefore, it might be one of the reasons why the estimated prevalence of the GCK-diabetes seems to be higher than the real one as it has been reported in several studies.

[Genetics of monogenic forms of diabetes]. / Genetika monogénových foriem diabetu.

Monogenic diabetes mellitus is a type of diabetes, where genetics without any other factors is strong enough to cause the disease. According to the clinical features monogenic diabetes can be divided to the mild familial early onset diabetes, familial fasting hyperglycemia, diabetes with extrapancreatic features and neonatal diabetes mellitus. During the last several years the number of genes causing monogenic diabetes has continuously increased. The clinical picture of the monogenic diabetes is very heterogeneous, thus DNA analysis is required for identification of the diabetes etiology, which influences also the choice of treatment. This article is an overview of current knowledge on monogenic diabetes, focusing at the clinically and epidemiologically most important forms.