Bioglobe (Germany)

BackgroundHypophosphataemic rickets (HR) comprise a clinically and genetically heterogeneous group of conditions, defined by renal-tubular phosphate wasting and consecutive loss of bone mineralisation. X-linked hypophosphataemia (XLH) is the most common form, caused by inactivating dominant mutations in PHEX, a gene encompassing 22 exons located at Xp22.1. XLH is treatable by anti-Fibroblast Growth Factor 23 antibody, while for other forms of HR such as therapy may not be indicated. Therefore, a genetic differentiation of HR is recommended.ObjectiveTo develop and validate a next-generation sequencing panel for HR with special focus on PHEX.Design and methodsWe designed an AmpliSeq gene panel for the IonTorrent PGM next-generation platform for PHEX and ten other HR-related genes. For validation of PHEX sequencing 50 DNA-samples from XLH-patients, in whom 42 different mutations in PHEX and 1 structural variation have been proven before, were blinded, anonymised and investigated with the NGS panel. In addition, we analyzed one known homozygous DMP1 mutation and two samples of HR-patients, where no pathogenic PHEX mutation had been detected by conventional sequencing.ResultsThe panel detected all 42 pathogenic missense/nonsense/splice-site/indel PHEX-mutations and in one the known homozygous DMP1 mutation. In the remaining two patients, we revealed a somatic mosaicism of a PHEX mutation in one; as well as two variations in DMP1 and a very rare compound heterozygous variation in ENPP1 in the second patient.ConclusionsThis developed NGS panel is a reliable tool with high sensitivity and specificity for the diagnosis of XLH and related forms of HR.

The diagnosis of cystic fibrosis (CF) is commonly confirmed by molecular genetics with the presence of specific mutations of cystic fibrosis transmembrane conductance regulator (CFTR) gene. We report a case of cystic fibrosis (CF) in a 15-year-old female patient who is a compound heterozygote for CFTR gene, with delta F508 and Tyr109Glyfs mutations detected. This is the first detailed description of such a case in the medical literature. The primary CF presentation occurred at the age of 9 in the form of gastrointestinal symptoms including greasy, bulky, and foul-smelling stool. The patient exhibited delayed growth, with her height and weight being below the 5th centile for age according to the World Health Organization growth curves. Pancreatic enzyme supplement treatment was started immediately, alongside high-fat and high-calorie diet, resulting in patient’s recovery and development. DNA analysis of CFTR gene demonstrated the presence of del. F508 mutation and a rare combining deletion and insertion mutation p. Tyr109Glyfs. The combination of the two mutations is very rare in CF patients and is therefore valuable to document this case in order to provide information on disease progression, therapy options, and outcomes. With standard treatment and early diagnosis, the patient is currently doing well and is not restricted by the disease in her daily and sports activities.

Resistance to thyroid hormone (RTH) is a syndrome of reduced responsiveness of target tissues to thyroid hormone (TH). Patients with RTH are identified by persistent elevation of circulating free TH levels with non-suppressed serum TSH. The underlying genetic defect is usually, but not always, a mutation in the TRβ gene. The frequency of de novo mutations is estimated to 21%. The inheritance is autosomal dominant. The clinical presentation varies significantly among different patients. However, goiter and the absence of neuropsychological symptoms and metabolic sequences of TH excess belong to the common features of the syndrome.

The high homology between the CYP21A2 (cytochrome P450, family 21, subfamily A, polypeptide 2) and CYP21A1P (cytochrome P450, family 21, subfamily A, polypeptide 1 pseudogene) genes is the major obstacle to risk-free genetic diagnosis of congenital adrenal hyperplasia, especially regarding the quantification of gene dosage. Because of the lack of a comprehensive study providing useful information about the detailed genetic structure of CYP21A1P, we used a large data set to analyze and characterize this pseudogene. We amplified and directly sequenced the CYP21A1P and CYP21A2 genes of 200 unrelated individuals. The resulting sequence data were aligned against the manually curated transcript ENST0000448314 from Havana/Vega matching to the genebuild ENSG00000198457; all differences were documented. Copy number was measured by multiplex ligation-dependent probe amplification when necessary. We found that 40 potentially variable positions in CYP21A2 were conserved in CYP21A1P in all study participants. In addition, we detected 14 CYP21A1P variants that were not previously reported in either CYP21A2 or CYP21A1P. Unlike CYP21A2, CYP21A1P possessed certain mutation haplotypes. The genetic structure of CYP21A1P and the potential risks of false conclusions it may introduce are essential considerations in designing a PCR-based diagnosis procedure for congenital adrenal hyperplasia.

objectives. For patients with borderline personality disorder (BPD), we previously reported an independent effect of the catechol-o-methyl-transferase (COMT) low-activity (Met158) allele and an interaction with the low-expression allele of the deletion/insertion (short/long or S/L, resp.) polymorphism in the serotonin transporter-linked promoter region (5-HTTLPR). The purpose of the present study was to extend these findings to the tyrosine hydroxylase (TH) Val81Met single nucleotide polymorphism (SNP), the 5-HTTLPR S/L polymorphism incorporating the recently described functional A/G SNP within the long allele of the 5-HTTLPR (rs25531) as well as the variable number of tandem repeat (VNTR) polymorphism within intron 2 of the serotonin transporter gene (STin2). Methods. In 156 Caucasian BPD patients and 152 healthy controls, we tested for association between BPD and the TH Val81Met SNP, the 5-HTTLPR/rs25531 polymorphism, the STin2, the interaction of the TH Val81Met SNP with the tri-allelic 5-HTTLPR/rs25531, the interaction of the TH Val81Met SNP with STin2. Results. Between BPD patients and controls, we observed a slight over-representation of the TH Met81Met genotype in BPD patients compared to controls, but no statistically significant differences in genotype distribution of the individual markers after adjusting for multiple testing. Logistic regression analysis showed a lack of interaction between the TH Val81Met and the 5-HTTLPR/rs25531 as well as between the TH Val81Met and the STin2 polymorphism. Conclusions. These data do not suggest independent or interactive effects of the TH Val81Met, the 5-HTTLPR/rs25531, or the STin2 polymorphisms in BPD.

Impulsive aggression is a key feature of Borderline Personality Disorder (BPD), which is suggested to play an important role for the suicide risk of BPD patients. It is believed to be determined by a complex interplay of genetic vulnerability, socio-cultural factors, personality traits and comorbid psychiatric disorders. The COMT Val158Met polymorphism has been investigated for its potential role in the regulation of aggression in male schizophrenia patients and in children with attention-deficit hyperactivity disorder as well as in the regulation of emotional arousal. 112 female BPD patients from Germany were included in the study. Impulsive aggression was assessed by the Buss-Durkee-Hostility Inventory (BDHI), SLEs by the PTSD-section included in the Munich-Composite International Diagnostic Interview (M-CIDI). We analyzed 1) the effects of serious life events (SLEs) on impulsive aggression, and 2) modulating effects of the COMT Val158Met polymorphism on the relation between SLEs and impulsive aggression in female BPD patients. Regression analyses confirmed a decreasing effect of childhood sexual abuse (CSA) on BDHI sum score as well as a decreasing effect of CSA and the cumulative number of SLEs on BDHI sum score in COMT Val/Val carriers. The study analyzing a specific gene x environment interaction in female BPD patients suggests a decreasing effect of SLEs on impulsive aggression in the total group and in COMT Val/Val carriers