Chromosome 7, monosomy

Chromosome 7, monosomy is a rare chromosomal abnormality involving the loss of one copy of chromosome 7 in a human's cells. In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Chromosome 7 is one of these pairs. When an individual has monosomy 7, they have only one copy of chromosome 7 instead of the usual pair, leading to various developmental and health issues. This condition is also known as monosomy 7 syndrome.

Causes

Monosomy 7 can occur due to errors in cell division, specifically during the processes of meiosis or mitosis. In meiosis, which is the division process that produces gametes (sperm and eggs), an error may lead to a gamete with an incorrect number of chromosomes. If a gamete missing chromosome 7 fertilizes with a normal gamete, the resulting embryo will have monosomy 7. Similarly, mitotic errors after fertilization can lead to monosomy 7 in some or all cells of the developing embryo.

Symptoms

The symptoms of monosomy 7 can vary widely among affected individuals, depending on the extent of the chromosomal abnormality and other genetic factors. Common symptoms include growth retardation, developmental delay, learning disabilities, and distinctive facial features. Some individuals may also have heart defects, kidney abnormalities, and issues with bone marrow function, which can lead to an increased risk of infections and other hematologic complications.

Diagnosis

Diagnosis of monosomy 7 typically involves genetic testing and chromosomal analysis through techniques such as karyotyping or fluorescence in situ hybridization (FISH). These tests can identify the presence of a single copy of chromosome 7 in cells.

Treatment

There is no cure for monosomy 7, and treatment focuses on managing the symptoms and complications associated with the condition. This may include educational support for learning disabilities, medical management of heart or kidney problems, and regular monitoring for potential issues with bone marrow function. In some cases, bone marrow transplant may be considered for individuals with severe hematologic complications.

Prognosis

The prognosis for individuals with monosomy 7 varies depending on the severity of symptoms and the presence of associated health issues. Early intervention and supportive care can improve the quality of life for many affected individuals.