appearance of autosomal recessive trait result in a condition called
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get appearance of autosomal recessive trait result in a condition called from screen.
Definition of autosomal recessive inheritance
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autosomal recessive inheritance
(AW-toh-SOH-mul reh-SEH-siv in-HAYR-ih-tunts)
One of the ways a genetic trait or a genetic condition can be inherited. In autosomal recessive inheritance, a genetic condition occurs when one variant is present on both alleles (copies) of a given gene.
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Autosomal recessive inheritance is a way a genetic trait or condition can be passed down from parent to child. A genetic condition can occur when the child inherits one copy of a mutated (changed) gene from each parent. The parents of a child with an autosomal recessive condition usually do not have the condition. Unaffected parents are called carriers because they each carry one copy of the mutated gene and can pass it to their children.
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Autosomal Recessive Disorder
Autosomal Recessive Disorder
The autosomal recessive disorder proximal spinal muscular atrophy (SMA) is a severe neuromuscular disease characterized by degeneration of alpha motor neurons in the spinal cord, which results in progressive proximal muscle weakness and paralysis.
From: Spinal Muscular Atrophy, 2017
Related terms:
ChromosomeEnzymeProteinPhenotypeDNAAlleleAutosomal Dominant InheritanceAutosomal Recessive InheritanceCystic Fibrosis
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Basic Genetic Principles
Fred Levine, in Fetal and Neonatal Physiology (Third Edition), 2004
Autosomal Recessive Disorders
AR disorders are those that are clinically apparent only when the patient is homozygous for the disease (i.e., both copies of the gene are mutant). The following pattern of inheritance is characteristic of AR disorders (see Fig. 1-7 B):
1.
The parents of affected children may be clinically normal (i.e., carriers).
2.
Assuming that the carrier frequency in the population is low, only siblings are affected, and vertical transmission does not occur; the pattern therefore tends to appear horizontal.
3.
Males and females are affected in equal proportions.
4.
When both parents are heterozygous carriers of the mutation, 25% of their children are affected, 50% are carriers, and 25% are normal.
Every person is a carrier of certain AR mutations. Fortunately, the carrier frequency for most of these mutations is so low that likelihood that carriers will have affected children is low.
Recessive mutations frequently involve enzymes, as opposed to regulatory and structural proteins. This is because 50% of the normal level of enzyme activity is usually sufficient for normal function. Complete enzyme deficiency produces an accumulation of one or more metabolites preceding the enzymatic block, such as the build-up of phenylalanine in phenylketonuria, and a deficiency of metabolites distal to the block. Either, or both, of these abnormalities may be responsible for the disease phenotype. Although many recessive disorders involve enzymes, two of the most common AR disorders are cystic fibrosis, resulting from a mutation in a chloride channel, and sickle cell anemia, resulting from a mutation in the β-globin gene.
The terms dominant and recessive refer to phenotypes only and have their greatest application at the clinical level. At the gene level, dominance and recessiveness do not exist. Persons heterozygous for a recessive disorder may be clinically normal, but the reduced level of functional or immunoreactive protein is usually detectable analytically and may lead to other biochemical abnormalities that have no obvious effect on the person's health. In addition, patients homozygous for dominant mutations are usually more severely affected than are heterozygous patients, as is true in familial hypercholesterolemia. In many cases, the homozygous condition results in embryonic lethality and is never seen. Huntington disease stands out as a major exception in that homozygous patients are not clinically different from heterozygous patients.
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Lysosomal Storage Diseases With Predominantly Histiocytic Storage
In Diagnostic Pathology: Blood and Bone Marrow (Second Edition), 2018
ETIOLOGY/PATHOGENESIS
Gaucher Disease
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Autosomal recessive disease caused by mutations in GAB
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GAB encodes acid β-glucocerebrosidase (a.k.a. glucosylceramidase), which breaks down glucocerebroside into glucose and ceramide
Niemann-Pick Disease
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Autosomal recessive disease of lipid metabolism
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Types A and B are caused by SMPD1 mutations
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SMPD1 encodes lysosomal acid sphingomyelinase
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Deficiency of sphingomyelinase leads to accumulation of sphingomyelin
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Type C is caused by mutations in NPC1 or NPC2
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NPC1 and NPC2 both encode proteins involved in intracellular binding and transport of exogenous cholesterol
Mucolipidosis I (Sialidosis)
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Autosomal recessive disease caused by mutations in NEU1
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NEU1 encodes α-N-acetyl neuraminidase-1, which removes sialic acid residues
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In absence of neuraminidase, sialylated glycopeptides and oligosaccharides accumulate
Cystinosis
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Autosomal recessive disease caused by mutations in CTNS
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CTNS encodes cystinosin, transport protein involved in export of cystine from lysosomes
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In absence of cystinosin, cystine is trapped in crystallized form within lysosomes
GM1 Gangliosidosis
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Autosomal recessive disease caused by mutations in GLB1
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GLB1 is same gene implicated in mucopolysaccharidosis IVB (Morquio B)
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Clinical description as GM1 gangliosidosis vs. mucopolysaccharidosis IVB depends on predominance of sphingolipid or glycosaminoglycan accumulation, respectively
α-Mannosidosis
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Autosomal recessive disease caused by mutations in MAN2B1
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MAN2B1 encodes α-mannosidase
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α-mannosidase assists in degradation of oligosaccharides, which contain mannose
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β-mannosidosis, in contrast, has been reported in only a few individuals and will not be further discussed here
Fucosidosis
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Autosomal recessive disease caused by mutations in FUCA1
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FUCA1 encodes α-L-fucosidase
Autosomal Recessive Disorder
Autosomal recessive is a pattern of inheritance characteristic of some genetic disorders.
Autosomal Recessive Disorder
updated: March 17, 2023
Definition
00:00 00:57
Autosomal recessive is a pattern of inheritance characteristic of some genetic disorders. “Autosomal” means that the gene in question is located on one of the numbered, or non-sex, chromosomes. “Recessive” means that two copies of the mutated gene (one from each parent) are required to cause the disorder. In a family where both parents are carriers and do not have the disease, roughly a quarter of their children will inherit two disease-causing alleles and have the disease. By contrast, an autosomal dominant disorder requires only a single copy of the mutated gene from one parent to cause the disorder. Sickle cell anemia is an example of an autosomal recessive genetic disorder.
Narration
00:00 00:44
Autosomal Recessive Disorder. The key thing about recessive disorders is that we all have two copies of every gene: one from mom, one from dad. For some, but not all genes, you really only need one working copy, and so it's only when both copies don't work that problems can occur. The most common way that people end up with two nonworking copies of a gene is when they get one each from mom and dad. Outside of sickle cell disease, other common autosomal recessive diseases include cystic fibrosis and very many of the genetic diseases that, at least in the United States, are screened for as part of newborn screening programs.
Neil A. Hanchard, M.B.B.S., D.Phil.
Senior Investigator
Center for Precision Health Research
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Related
Autosomal Dominant Disorder
Chromosome
Deoxyribonucleic Acid (DNA)
Mutation
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