What are inherited retinal dystrophies?5 answersInherited retinal dystrophies (IRDs) are a group of genetic disorders affecting the retina, leading to vision loss. These diseases result from defects in genes associated with photoreceptor and retinal pigment epithelium function, disrupting pathways critical to vision. IRDs exhibit high genetic and phenotypic heterogeneity, with various inheritance patterns like dominant, recessive, X-linked, and mitochondrial. Studies in Spain and Portugal have highlighted the prevalence and genetic landscape of IRDs, emphasizing the importance of molecular diagnosis for proper management and genetic counseling. Research in Arab populations has shown a high degree of homozygosity in IRD mutations, often due to consanguinity, with specific genes like TULP1, ABCA4, and RP1 being commonly mutated. Additionally, investigations in consanguineous Pakistani families have identified novel and reported pathogenic mutations associated with night blindness in IRDs.
What are inherited retinal dystrophies?5 answersInherited retinal dystrophies (IRDs) are a group of genetic diseases that affect the retina and lead to degeneration of retinal cells, ultimately causing vision loss. These diseases have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. IRDs primarily affect retinal photoreceptors and pigment epithelial cells, leading to neurodegeneration and apoptosis. They are characterized by an elevated genetic and clinical heterogeneity, with more than 280 disease genes identified so far. Mutations in over 300 genes have been associated with syndromic and non-syndromic IRDs. IRDs can present with different clinical phenotypes, such as retinitis pigmentosa, Stargardt disease, Usher syndrome, cone-rod dystrophy, cone dystrophy, and Leber congenital amaurosis. Genetic testing plays a crucial role in the diagnosis and management of IRDs, as it helps identify the causative genetic variants and provides important information for genetic counseling.
Whate is the rare Rh phenotype4 answersThe rare Rh phenotype is characterized by the lack of expression of all Rh antigens (D, C, c, E, and e) on the red blood cells. This phenotype is associated with chronic hemolytic anemia and the formation of alloantibodies when exposed to Rh antigens. It is transmitted via an autosomal recessive mode and has a frequency of approximately 1 in 6 million individuals. The D-phenotype is a specific type of rare Rh variant in which none of the RhCE antigens are expressed on the red cell surface. Individuals with the D-phenotype are capable of producing a rare alloantibody known as anti-Rh17(Hrₒ) in response to pregnancy or transfusion, which can cause severe hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. Another rare Rh phenotype is ccDEE, which has an incidence in the population ranging from 0.34% to 1.99% and has been associated with hemolytic disease of the newborn.
Can SGCB mutations cause muscular dystrophy?5 answersSGCB mutations are not mentioned in the provided abstracts as a cause of muscular dystrophy.
What is rare genetic diseases?4 answersRare genetic diseases are disorders that affect a small portion of the population, with a prevalence of less than 1 in 2000 individuals. These diseases often have a genetic component and can be life-threatening or seriously debilitating. The diagnostic process for rare genetic diseases typically involves a combination of clinical practices, such as physical examination, personal and family history, laboratory tests, and imaging studies. However, the diagnosis of rare genetic diseases can be delayed for several years after the onset of symptoms. Advances in molecular genetics have significantly impacted the diagnosis and treatment of rare diseases, providing a better understanding of the underlying mechanisms and offering tools for diagnosis. For example, the study of rare genetic diseases has led to the discovery of fundamental mechanisms required for human development and common diseases.
What are some examples of rare alleles?5 answersRare alleles are genetic variations that occur at a low frequency in a population. Examples of rare alleles mentioned in the abstracts include specific mutations or polymorphisms associated with schizophrenia, unique alleles in Przewalski's horse and California Condor populations, rare alleles at the MHC (major histocompatibility complex) in endangered species, genetic polymorphisms in the iron-binding protein transferrin, and rare alleles in the VNTR region flanking the Ha-ras I gene in testicular cancer patients. These examples highlight the diversity of rare alleles across different species and genetic traits.