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Genetic Counseling in Assisted Reproductive Technology
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Autosomal recessive inheritance is when mutation in both alleles of an autosomal disease is necessary to cause disease. An affected individual has two non-functional alleles, one inherited from each carrier parent. An individual carrying a single variant in a recessive gene is unaffected with the condition, but when two individuals are carriers, there is a 25% chance that both variants will be passed on, resulting in an affected child. There may be no family history of a recessive condition when a child is found to be affected. The variant can be passed down generation to generation without ever causing disease until, by random chance, both members of a reproductive couple are carriers, and future offspring are at risk of being affected. Carrier screening can therefore be an effective tool in detecting such carrier couples.
Unusual Inherited Pulmonary Diseases Which Provide Clues to Pulmonary Physiology and Function
Published in Stephen D. Litwin, Genetic Determinants of Pulmonary Disease, 2020
Thomas Κ. C. King, Robert A. Norum
Several studies have documented the increased incidence of scoliosis among the relatives of the patient with this disorder [161-165]. In addition, there is a clear female preponderance which has led to the suggestion that transmission is possibly through a sex-linked dominant gene [165]. Evidence against this is a report of a father-to-son transmission [163]. Furthermore, analysis of the frequency of scoliosis among relatives shows the incidence in first-degree relatives to be lower than expected as well as a sharp fall off in the second-and third-degree relatives. There is, therefore, no simple predictable pattern of inheritance as might be expected with a dominant or recessive gene. Twin studies have tended to show a high rate of concordance among both monozygotic and dizygotic pairs and favor maternal factors as being important [164, 166]. Thus, the evidence to date on the mode of transmission is inconclusive. While there is little doubt that hereditary factors play a part in about one-quarter of the patients with idiopathic scoliosis, the extent to which these determine the outcome may be different in different cases. In some, the transmission may be dominant, in others, multifactorial and both subject to modification by environmental factors. Indeed, the variability of the findings may reflect the heterogeneity of a disorder which has been, in the present state of knowledge, viewed as a single group.
Glycogenosis type III/amylo-1, 6-glucosidase (debrancher) deficiency
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
The disorder is transmitted by an autosomal recessive gene. Heterozygote detection has been carried out by the assay of debrancher enzyme activity in leukocytes and erythrocytes; intermediate levels were obtained [12, 45–47]. In families in which the patient lacks immunoprecipitable debrancher protein, carrier detection can be accomplished by Western blot [48].
Association of TLR2 and TLR9 gene polymorphisms with atopic dermatitis: a systematic review and meta-analysis with trial sequential analysis
Published in Immunological Medicine, 2023
Boyang Zhou, Surong Liang, Shuai Shang, Linfeng Li
A total of eight studies were included in our meta-analysis [9,10,14,22–26]. Among these studies, seven reported TLR2 gene rs5743708 polymorphism, with 636 AD patients included [9,10,14,22–25]; three reported TLR2 gene rs4696480 polymorphism, with 393 patients [9,10,14]; two reported TLR9 gene rs5743836 and rs187084 polymorphisms, with 407 and 408 patients [14,26]. The included studies were all case-control studies. In the study groups, the patients varied from 13 to 272, and the control subjects varied from 6 to 247. In two studies [22,23], only the frequencies of patients carrying recessive gene was provided, as a result, the amounts of alleles could not be obtained, also in the two studies, the HWE could not be test. All other studies provided precise number of gene types, which the amounts of alleles could be calculated. The HWE could also be test in those studies, and all the study groups complied with HWE (Table 1, sTable 1 in Supplementary material).
UK guidelines for the medical and laboratory procurement and use of sperm, oocyte and embryo donors (2019)
Published in Human Fertility, 2021
Helen Clarke, Shona Harrison, Marta Jansa Perez, Jackson Kirkman-Brown
Furthermore, the potential donor should ordinarily not be heterozygous for an autosomal recessive gene known to be prevalent in the donor’s ethnic background. This includes: (i) cystic fibrosis in Caucasian populations; (ii) glucose-6-phosphate dehydrogenase deficiency or ∝0 or β-Thalassaemia in Mediterranean populations; (iii) sickle cell disease in African & Afro-Caribbean populations; and (iv) Tay-Sachs disease in Jews of Eastern European descent. However, in exceptional circumstances (e.g. in cases of known donation) the presence of a recessive gene disorder may not necessarily be a contraindication to donation provided that, when the donation is used, all parties are fully informed, the view of an appropriately qualified clinical geneticist is obtained and full records are kept. The decision whether or not to proceed should consider the type of treatment being offered as well as the genetic profile of the donor and recipient couple.
The utility of whole exome sequencing in diagnosing neurological disorders in adults from a highly consanguineous population
Published in Journal of Neurogenetics, 2019
Weiyi Mu, Nicoline Schiess, Jennifer L. Orthmann-Murphy, Ayman W. El-Hattab
Retrospective chart review was performed on 24 adults with undiagnosed neurologic disorders who were evaluated at genetics and neurology clinics at Tawam Hospital in Al Ain, United Arab Emirates between 2014 and 2016 and had WES testing. Data regarding clinical symptoms, neuroimaging results, family history, and genetic testing results were collected. Consanguinity was noted if the individual’s parents were second cousins or closer in relation. All patients underwent trio WES if parents were available, and proband-only WES if parents were unavailable, by accredited commercial laboratories in Europe or the United States, namely Baylor Genetics Laboratories in Houston, TX; Prevention Genetics in Marshfield, WI; and Centogene in Rostock, Germany. Potentially causative variants underwent Sanger confirmation, and were classified by the laboratory according to the 2015 American College of Medical Genetics guidelines (Richards et al., 2015). Patients were consented for primary and secondary variants, as recommended by ACMG guidelines (Kalia et al., 2017), identified from WES by the clinical genetics team. If clinically indicated, follow-up familial segregation was performed; this included parental testing to determine if two variants in the same recessive gene were biallelic or confirming segregation of likely pathogenic variants in affected siblings. Each of the WES cases were deemed “positive” if a likely disease-causing variant was identified and “negative” if no causative variants were identified. This study was approved by the Al-Ain Medical District Human Research Ethics Committee.