In medical genetics, compound heterozygosity is the condition of having two or more heterogeneous recessive alleles at a particular locus that can cause genetic disease in a heterozygous state; that is, an organism is a compound heterozygote when it has two recessive alleles for the same gene, but with those two alleles being different from each other (for example, both alleles might be mutated but at different locations). Compound heterozygosity reflects the diversity of the mutation base for many autosomal recessive genetic disorders; mutations in most disease-causing genes have arisen many times. This means that many cases of disease arise in individuals who have two unrelated alleles, who technically are heterozygotes, but both the alleles are defective.
These disorders are often best known in some classic form, such as the homozygous recessive case of a particular mutation that is widespread in some population. In its compound heterozygous forms, the disease may have lower penetrance, because the mutations involved are often less deleterious in combination than for a homozygous individual with the classic symptoms of the disease. As a result, compound heterozygotes often become ill later in life, with less severe symptoms. Although compound heterozygosity as a cause of genetic disease had been suspected much earlier, widespread confirmation of the phenomenon was not feasible until the 1980s, when polymerase chain reaction techniques for amplification of DNA made it cost-effective to sequence genes and identify polymorphic alleles.
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In medical genetics, compoundheterozygosity is the condition of having two or more heterogeneous recessive alleles at a particular locus that can cause...
LRPPRC gene, located on the small ('p') arm of chromosome 2. Both compoundheterozygosity and homozygous mutations have been observed in French Canadian...
Horst GT, Hoeijmakers JH, Mitchell JR (November 2012). "Effects of compoundheterozygosity at the Xpd locus on cancer and ageing in mouse models". DNA Repair...
"Pseudoxanthoma Elasticum Is a Recessive Disease Characterized by CompoundHeterozygosity" - Journal of Investigative Dermatology "Molecular Genetics of...
β-thalassemia), while those who have two gene mutations (homozygosity or compoundheterozygosity) are diagnosed with β-thalassemia or intermedia. Due to the lack...
are inherited as autosomal recessive traits with homozygosity or compoundheterozygosity for two defective TNSALP alleles. The mode of inheritance for childhood...
girl with Fraser syndrome, Slavotinek et al. (2006) identified compoundheterozygosity for a deletion (607830.0006) and an insertion (607830.0007) in...
has variable penetrance in some pedigrees) With homozygosity or compoundheterozygosity - depending on the exact mutations involved, individuals may lie...
mutations in exons 1 (Gln1 to Stop) and 36 (Arg1458 to Stop) and compoundheterozygosity in three African-American families". J. Immunol. 154 (10): 5464–71...
Ramaekers, FC; Steijlen, PM; Kamps, M; Kuijpers, HJ; et al. (2006). "Compoundheterozygosity for mutations in LMNA causes a progeria syndrome without prelamin...
syndrome often suffer from heart failure in teenage years. A case of compoundheterozygosity for two DSP nonsense mutations resulting in lethal acantholytic...
T, Patel PI (May 1997). "Atypical Friedreich ataxia caused by compoundheterozygosity for a novel missense mutation and the GAA triplet-repeat expansion"...
diminished in number and degenerated. LAAHD disease results from compoundheterozygosity of GLE1FinMajor and a missense point mutation in exon 13 (6 cases...
S2CID 205223048. Castoldi E, Collins PW, Williamson PL, Bevers EM (2011). "Compoundheterozygosity for 2 novel TMEM16F mutations in a patient with Scott syndrome"...
Vitale L, Prete A, Locatelli F, Bagnara GP, Paolucci G (2000). "Compoundheterozygosity for two different amino-acid substitution mutations in the thrombopoietin...
fibrinogen Marburg, and fibrinogen Sfax. Two different mutations (see Compoundheterozygosity) occur in each of the two copies of one of the cited genes, with...
"Mitochondrial encephalomyopathy and retinoblastoma explained by compoundheterozygosity of SUCLA2 point mutation and 13q14 deletion". European Journal...
(2007). "Autosomal recessive postlingual hearing loss (DFNB8): compoundheterozygosity for two novel TMPRSS3 mutations in German siblings". J. Med. Genet...
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