Biomedical subjects

Magdalena Nawara

Publications and source records attributed to Magdalena Nawara.

6 recordsLinked to original sources

PubMed2006

The ARX mutations: a frequent cause of X-linked mental retardation.

The ARX gene mutations have been demonstrated to cause different forms of mental retardation (MR). Beside FMR1, in families with X-linked mental retardation (XLMR), the ARX dysfunction was demonstrated to be among the most frequent causes of this heterogeneous group of disorders. Nevertheless, in sporadic cases of MR, ARX mutations are extremely rare. In order to evaluate the frequency of ARX mutation in XLMR, we performed mutational analysis of ARX in 165 mentally retarded probands negative for FRAXA and belonging to families in which the condition segregates as an X-linked condition. The same recurrent mutation, an in frame 24 bp insertion (c.428-451 dup (24 bp)), was identified in five patients. In one family, the mother of two affected boys was found not to carry the mutation detected in her sons. These data suggest the presence of germline mosaicism for the mutation in the mother. Our results confirm the significant contribution of ARX mutations in the etiology of MR, especially in this group of patients selected for XLMR (3%). These data, together with those reported in the literature, imply that screening for c.428-451 dup (24 bp) mutation should be recommended in all patients with suspected XLMR.

Adolescent↗

PubMed2006

Molecular analysis of defects in the CFTR gene and AZF locus of the Y chromosome in male infertility.

OBJECTIVE: To investigate the frequency and potential impact of mutations and polymorphisms in the CFTR gene and deletions in AZF locus of the Y chromosome in patients with azoospermia (AZOO), cryptozoospermia (CRYPTO) or oligoasthenoteratozoospermia (OAT) who were to be included in an assisted reproductive technologies (ART) program. STUDY DESIGN: A total of 188 infertile men were enrolled in the study: 100 patients with AZOO, 38 with CRYPTO and 50 with OAT. RESULTS: The CFTR gene mutations or IVS8-5T variant in at least 1 allele was identified with similar frequencies among the AZOO (33%) and CRYPTO (21%) patients; 55% of the AZOO patients with normal spermatogenesis (NS) had mutations in 1 or 2 alleles. The novel R810G mutation in exon 13 was identified in 1 NS patient. The OAT or AZOO patients with Sertoli cell only syndrome (SCO) had mutations in the CFTR gene with similar frequencies to that in the general Polish population. The deletions in the AZF locus were detected in 20% of SCO patients, 11.5% of AZOO patients with maturation arrest and in 5% of CRYPTO patients. The other groups (NS, OAT) did not carry deletions in the region studied. CONCLUSION: Molecular diagnosis of the CFTR gene, Y chromosome deletion analysis and genetic counseling are necessary diagnostic elements for patients with male infertility, especially if the are included in an ART program.

Adult↗

PubMed2002

Aerobic and anaerobic NAD+ metabolism in Saccharomyces cerevisiae.

In Saccharomyces cerevisiae the nicotinic acid moiety of NAD+ can be synthesized from tryptophan using the kynurenine pathway or incorporated directly using nicotinate phosphoribosyl transferase (NPT1). We have identified the genes that encode the enzymes of the kynurenine pathway and for BNA5 (YLR231c) and BNA6 (YFR047c) confirmed that they encode kynureninase and quinolinate phosphoribosyl transferase respectively. We show that deletion of genes encoding kynurenine pathway enzymes are co-lethal with the Deltanpt1, demonstrating that no other pathway for the synthesis of nicotinic acid exists in S. cerevisiae. Also, we show that under anaerobic conditions S. cerevisiae is a nicotinic acid auxotroph.

Aerobiosis↗

PubMedDate not supplied

[Monogenic causes of nonspecific X-linked mental retardation molecular aspects].

Mental retardation (MR) is a symptom in a large group of clinical conditions and affects around 3% of the population. MR is divided into syndromic, if it is characterized by distinctive clinical features and nonspecific when mental retardation is the only defining manifestation. Although genetic causes of X-linked mental retardation (XLMR) are heterogenous and complex, recent findings have led to the identification of an increasing number of genes involved in these conditions. Eight genes involved in nonspecific X-linked mental retardation have been identified so far, including FMR2, GDI1, OPHN1, PAK3, ARHGEF6, IL1RAPL, TM4SF2, and FACL4. Four other MECP2, RSK2, ARX, ATR-X are involved in syndromic and nonspecific forms of MR. Recent research has shown that these genes encode for proteins involved in signaling pathways which regulate cytoskeleton organization, synaptic vesicle transport and establishment of connections between neuronal cells. These findings provide insight into the molecular mechanisms of crucial processes for the development of intellectual and cognitive functions.

Chromosomes, Human, X↗

PubMedDate not supplied

[I. Single nucleotide polymorphism in human genetic analyses].

The new era of human genetic analyses has been began by finishing of The Human Genome Project. Discovery of the almost complete sequence of human DNA showed surprisingly small differences between the genetic materials of randomly chosen people. Genetists pay intensive attention to the very small part of nucleotide sequence - 0.1% - which contains polymorphic changes. The most frequent type of these changes is polymorphism of a single nucleotide (SNP). It makes up about 90% of all molecular differences in human DNA sequence. There are about 3 mln positions in DNA sequence containing SNPs. Polymorphic changes serve as genetic markers and they enable to map genes or to follow their inheritance. Changes of this kind seem also to be the possible cause of the remarkable variety of susceptibility to many common diseases e.g.: diabetes, cancer and cardiovascular disorders. SNPs are also the object of interest of intensively developing scientific domain - pharmacogenetics. Scientists working on this interdisciplinary field - connecting pharmacology and genetics - try to find out the reason of great variety of response to medicines and their side effects in case of patients belonging to the same therapeutical groups. Progress in this kind of research in near future will enable a significant improvement of pharmacological therapy, which will be based on matching the drug to genetically determined traits of patients.

Genetic Markers↗

PubMedDate not supplied

[Attention deficit hyperactivity disorder (ADHD)--molecular and genetic aspects].

Attention deficit hyperactivity disorder (ADHD) is a common neurobehavioral disorder of childhood, affecting approximately 5-10% of children. ADHD is considered to be a multifactorial disorder because both genetic and environmental components may contribute to its progress. The etiology of attention deficit hyperactivity disorder (ADHD) is unknown, however family, twin and adoption studies have suggested that genetic factors are very important in its etiopathogenesis. The research of genetic basis of ADHD consists of linkage analysis, candidate gene approach and association studies. These analyses and also investigations on animal models of disease suggest that mutations in genes involved in dopaminergic, serotonergic and adrenergic systems are likely to be responsible for ADHD.

Attention Deficit Disorder with Hyperactivity↗