Ring chromosomes are rare chromosomal disorders that usually appear to occur de novo. A ring chromosome forms when due to deletion both ends of chromosome fuse with each other. Depending on the amount of chromosomal deletion, the clinical manifestations may be different. So, ring 18 syndrome is characterized by severe mental growth retardation as well as microcephaly, brain and ocular malformat...

bjective: To review a 12-year experience of the world’s three largest preimplantation genetic diagnosis PGD) centers. esign: Multicenter analysis of the clinical outcome of PGD. etting: In vitro fertilization programs at the Reproductive Genetics Institute, Chicago, Illinois; Saint arnabas Medical Center, West Orange, New Jersey; and SISMER, Bologna, Italy. atient(s): Poor-prognosis IVF patient...

complex inherited diseases affected by an interaction between collective effects of the genotype at one or multiple loci either to increase or to lower susceptibility to disease, combined with a variety of environmental exposures that may trigger, accelerate, exacerbate, or protect against the disease process. the new aspects of genetic techniques have been opened for diagnosis and analysis of ...

DNA cytophotometry was used to quantify the chromosomal alterations in the bone marrow and blood of three patients with nonspecific myeloid disorders. All patients possessed a popu lation of cells with a morphologically abnormal chromosome 20, del(2OXqll). In two of the patients, the abnormal chromo some 20 showed nearly identical DNA measurements with a net loss of 0.37% of the total autosomal...

Background: Sexual reproduction affords the stands for conserving genetic characteristics and sequentially, genetic inconsistency may influence the capability to imitate. Materials and Methods: Research was conducted by subject in PubMed and other databases. Results: A significant number of genotypes have been related with infertility phenotypes and evaluation of precise genes in humans and mod...

The fast technological development, particularly single nucleotide polymorphism array, array-comparative genomic hybridization, and whole exome sequencing, has led to the discovery of many novel genetic causes of growth failure. In this review we discuss a selection of these, according to a diagnostic classification centred on the epiphyseal growth plate. We successively discuss disorders in ho...

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are two distinct neurogenetic disorders in which imprinted genes on the proximal long arm of chromosome 15 are affected. Although the SNORD116 gene cluster has become a prime candidate for PWS, it cannot be excluded that other paternally expressed genes in the chromosomal region 15q11q13 contribute to the full phenotype. AS is caused by a d...

Background: In disorders of sexual differentiation, development may not conform to the chromosomal structure, thus forming different types abnormalities. Among these abnormalities is syndrome 46, XX DSD where most patients are female phenotype with clitoral hypertrophy that can go complete masculinization especially in presence SRY gene. Objective: The goal this work demonstrate a relationship ...

Of all the techniques available for microassisted reproduction, the direct injection of individual sperm cells or spermatids into the cytoplasm of the oocyte (ICSI) is the most invasive, through which any possible selection against sperm cells with genomic defects would be excluded. It has, however, been shown that such a possible selection is present neither in the female genital tract nor at ...

The current status of our knowledge of genetic diseases is reviewed. The incidence of monogenic, multifactorial and chromosomal disorders, according to the literature to date, is given, and the possibilities of mass screening programmes are discussed. The prospects for antenatal diagnosis of genetic diseases are reviewed, with emphasis on the indications for amniocentesis and the safety of the ...