What does it mean if you have a duplicate chromosome?

What does it mean if you have a duplicate chromosome?

​Duplication Duplication is a type of mutation that involves the production of one or more copies of a gene or region of a chromosome. Gene and chromosome duplications occur in all organisms, though they are especially prominent among plants. Gene duplication is an important mechanism by which evolution occurs.

What happens if you have an extra 1 chromosome?

1 duplication syndrome is a chromosomal disorder caused by duplication of a small piece of chromosome 1. The syndrome is characterized by features such as large head size, developmental delay, intellectual disabilities, typical facial features, cardiac problems, and seizures.

What is 22q duplication syndrome?

Overview. 22q11. 2 duplication syndrome is a condition caused by an extra copy of a small piece of chromosome 22 which contains about 30 to 40 genes. The features of this condition vary widely, even among members of the same family (intrafamilial variability).

How common is chromosome duplication?

Duplications are even less common, showing a prevalence of 0.7 per 10,000 births and representing ≍ 2% of all the chromosome abnormalities identified (Wellesley et al., 2012).

Is chromosome duplication harmful?

Duplication creates genetic redundancy, where the second copy of the gene is often free from selective pressure—that is, mutations of it have no deleterious effects to its host organism.

What disease does Duplication cause?

MECP2 duplication syndrome is a severe neurological and developmental disorder. Signs and symptoms include low muscle tone ( hypotonia ) in infancy, developmental delay , severe intellectual disability , and progressive spasticity . Other signs and symptoms may include recurrent respiratory infections and seizures .

Is duplication syndrome inherited?

MECP2 duplication syndrome is inherited in an X-linked pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes in each cell.

Is 22q duplication a disability?

The features of this condition vary widely, even among members of the same family. Affected individuals may have developmental delay, intellectual disability, slow growth leading to short stature, and weak muscle tone (hypotonia). Many people with the duplication have no apparent physical or intellectual disabilities.

Is 22q a disability?

Many children with 22q11. 2 deletion syndrome have developmental delays, including delayed growth and speech development, and some have mild intellectual disability or learning disabilities.

Is there a trisomy 1?

In all trisomies, trisomy 1 is the most rare case. There have so far only been three case reports of a full trisomy 1 in the literature.

What causes chromosomal duplication?

Duplications typically arise from an event termed unequal crossing-over (recombination) that occurs between misaligned homologous chromosomes during meiosis (germ cell formation). The chance of this event happening is a function of the degree of sharing of repetitive elements between two chromosomes.

Why might a chromosomal duplication be harmful?

Since a very small piece of a chromosome can contain many different genes, the extra genes present in a duplication may cause those genes to not function properly. These “extra instructions” can lead to errors in the development of a baby.

What is Microduplication of 1q21 1?

The duplication occurs on the long (q) arm of the chromosome at a location designated q21.1. Some people with a 1q21.1 microduplication have developmental delay and intellectual disability that is typically mild to moderate. Individuals with this condition can also have features of autism spectrum disorder.

What causes chromosome 1q21 duplication syndrome?

Chromosome 1q21.1 duplication syndrome can occur sporadically (by chance) from a de novo mutation or can be inherited in an autosomal dominant manner from a parent that has the same duplication. When the condition occurs sporadically, it is caused by a random error during the formation of the egg or sperm cell,…

What are the physical findings characteristic of microduplication?

As adults, individuals with a 1q21.1 microduplication may be prone to develop cysts, swollen and knotted (varicose) veins, or carpal tunnel syndrome, which is characterized by numbness, tingling, and weakness in the hands and fingers. However, there is no particular pattern of physical abnormalities that characterizes 1q21.1 microduplications.

What are the signs and symptoms of duplication syndrome?

Our patient has many clinical features previously reported with 1q21.1 duplication syndrome, including autism with intellectual disability, hyperactivity and impulsivity, macrocephaly, hypertelorism, and hypotonia. Microduplications have also been reported in “normal” individuals, subsequently often found to have subtle features of the disorder.