China
Africa
Explore chapters and articles related to this topic
Carrier Screening for Single-Gene Disorders
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Julio Martin, Arantxa Hervas, Ana Bover, Laura Santa, Ana Cervero
Carrier screening (CS) denotes genetic testing performed on an otherwise healthy, asymptomatic individual to determine whether that person has a mutation within a given gene associated with a recessive disorder; in addition, females are also tested for X-linked genes. It can be performed to test for a single condition, a limited number of specific conditions, or hundreds of disorders. Testing for many conditions simultaneously is known as expanded carrier screening (ECS). Remarkably, ECS will identify most individuals and couples who are at risk of having affected children. Nevertheless, it must be noted that any individual who tests negative for a specific mutant allele still has a residual risk (RR) of being a true carrier. This RR will vary depending on the disease prevalence, detection rate, and ethnicity, among other variables.
Abortion, Disability Rights, and Reproductive Justice
Published in Joel Michael Reynolds, Christine Wieseler, The Disability Bioethics Reader, 2022
Prenatal genetic testing provides genomic information, which is translated to prospective parents with the help of genetic counselors into presumptive knowledge about disability. But this knowledge is highly uncertain. This is the case at the level of modern scientific knowledge, where the meaning of a given variant may be highly probabilistic, and at the level of the meaning of disability, where category boundaries are fuzzy and socially as well as historically contingent. Some variants lead with a high enough probability to a particular phenotypic deviation from what medicine considers to be typical that they can be communicated as certain. At the other end of the spectrum, those known as “variants of unknown significance” offer uncertain meanings that might change over time (Johnston 2017). In other words, in some cases there is agreement by scientific and medical experts that X variant will lead to Y condition, in some cases there is contestation, and in some cases genomic information is little more than a shot in the dark.
Selected topics
Published in Henry J. Woodford, Essential Geriatrics, 2022
Electromyogram (EMG) testing is likely to show muscle denervation with preserved velocities when there is LMN involvement. Brain or spine imaging is likely to appear normal. Genetic testing can be considered for people with a family history. There is no curative treatment. Riluzole, a glutamate antagonist, improves survival at 12 months, but has no benefit on muscle strength. The median survival increase is around three to six months.65 Speech and language therapy can help with dysarthria and dysphagia. Tube feeding may be appropriate for selected people with dysphagia. Non-invasive ventilation can prolong survival in appropriate patients. Analgesia may be necessary for joint pains. Spasticity may be present. Advance care planning and palliative care are important aspects of management.
Disparities in Inherited Retinal Degenerations
Published in Seminars in Ophthalmology, 2023
Sarah Chorfi, Emily M. Place, Rachel M. Huckfeldt
Inherited retinal degenerations are a group of genetically and phenotypically diverse Mendelian retinal conditions affecting approximately 1 in 2,000 to 1 in 3,0001–3 individuals globally and typically resulting in significant visual impairment and blindness. Although these conditions have historically been untreatable, a steadily increasing genetic and molecular understanding of these conditions has resulted in one FDA-approved gene therapy for a particular type of IRD (Luxturna; voretigene neparvovec) and the hope of more therapies to come. Indeed, since the identification of the first IRD-associated genes over 30 years ago, the gradual diminution of cost and time for DNA sequencing has led to the identification of more than 280 IRD-related genes.4 Panel-based diagnostic genetic testing for IRDs yields a genetic explanation in up to 75% of patients.5–9 Of the remaining group of unsolved cases, whole exome and whole genome sequencing can find a disease-causing explanation in a significant proportion of patients (56% to 67%).10–12 Genetic testing can provide patients with a molecular diagnosis, which is powerful as it can provide an explanation for the condition, guide medical management, provide information on recurrence risk within families, and in some cases indicate eligibility for current and future gene-specific interventions. Genetic testing has now become a standard of care in many parts of the world.13
Reflex single-gene non-invasive prenatal testing is associated with markedly better detection of fetuses affected with single-gene recessive disorders at lower cost
Published in Journal of Medical Economics, 2022
Shan Riku, Herman Hedriana, Jacqueline A. Carozza, Jennifer Hoskovec
Autosomal recessive disorders represent a large disease burden worldwide1. Manifestation of autosomal recessive disorders in the first 25 years of life is estimated to be 1.7 in 1,0002 and can be considerably higher in certain populations3. Carrier screening is a genetic testing methodology that aims to identify individuals or couples who carry one variant allele within a gene and are at risk of having offspring with the associated genetic disorder4. The American College of Obstetricians and Gynecologists (ACOG) recommends all patients who are considering pregnancy or currently pregnant be carrier screened for cystic fibrosis (CF), spinal muscular atrophy (SMA), and hemoglobinopathies4. Most patients are screened after they become pregnant, with one 2019 study reported that 436 out of 462 patients (94.4%) undergoing carrier screening were screened prenatally5.
Toward genetic counseling practice standards for diagnostic testing in amyotrophic lateral sclerosis and frontotemporal dementia
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2022
Ashley Crook, Chris Jacobs, Toby Newton-John, Alison McEwen
As genotype-targeted therapy trials emerge for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), availability and interest in genetic testing will likely increase (1). Diagnostic testing is the initial genetic testing performed in families to search for a pathogenic variant (mutation). Diagnostic testing may occur as part of the process of confirming a clinical diagnosis of ALS/FTD in an individual, or later, after a clinical diagnosis is made to confirm whether a familial ALS/FTD pathogenic variant is present. Genetic counseling enables clients to make informed testing decisions while minimizing adverse outcomes and should accompany any genetic testing discussion. However, the amount of counseling required or recommended is unknown (2). We sought input from health professionals (HPs) and consumers to develop practice standards for genetic counseling when offering diagnostic testing for ALS and/or FTD.