Chromosomal Deletionssyndrome

Chromosomal deletions lead to a partial loss of the chromosome. They can cause severe congenital malformations and marked mental retardation. Syndromes of chromosomal deletion are rarely suspected prenatally, but can be discovered by chance during a karyotyping as a result of other causes. Postnatal diagnosis is believed by the clinical appearance and confirmed by karyotyping, if deletion is relatively large, or by other cytogenetic techniques such as fluorescence in situ hybridization, or microarray analysis.

Chromosomal Deletionssyndrome typically mean larger deletions that are visible typically in karyotype. Syndromes with small deletions (and its supplements), which affect one or more contiguous genes on a chromosome and are not visible in karyotype, are considered to be Microdeletions- and Duplikationssyndrome.

Chromosomal deletions lead to a partial loss of the chromosome. They can cause severe congenital malformations and marked mental retardation. Syndromes of chromosomal deletion are rarely suspected prenatally, but can be discovered by chance during a karyotyping as a result of other causes. Postnatal diagnosis is believed by the clinical appearance and confirmed by karyotyping, if deletion is relatively large, or by other cytogenetic techniques such as fluorescence in situ hybridization, or microarray analysis. Chromosomal Deletionssyndrome typically mean larger deletions that are visible typically in karyotype. Syndromes with small deletions (and its supplements), which affect one or more contiguous genes on a chromosome and are not visible in karyotype, are considered to be Microdeletions- and Duplikationssyndrome. 5p deletion (Cri-du-chat syndrome) The hallmark of the deletion of the short arm of chromosome 5 (5p – usually the father) is a hochtoniger, meowing cry that is strongly reminiscent of the cry of a cat, which typically early in the neonatal period is heard, several weeks continues and then disappears. The affected newborns have a hypotension and a low birth weight, microcephaly, an asymmetry of the face and / or a round moon face with wide-set eyes, antimongoloiden or downward eyelids with or without epicanthic folds, strabismus and a broad-nose. The ears are deep and are abnormally shaped, often have narrow ear canal and preauricular appendage. Syndactyly, hypertelorism and heart failure are common. The mental and physical development is significantly retarded. Many affected children experiencing adulthood, but are severely disabled. 4p deletion (Wolf-Hirschhorn syndrome) The deletion of the short arm of chromosome 4 (4p) results in a variable intellectual disability, people with larger deletions are heavier usually affected. Deposits can provide a wide, prominent nose, lying in the midline scalp defects, ptosis and coloboma, cleft palate, delayed bone age in boys and hypospadias and undescended testicles. Some patients with Wolf-Hirschhorn syndrome also have an immune deficiency. Many affected children die during infancy and the few who reach their third decade of life, are often severely disabled. Subtelomeric deletions These deletions may be visible on the karyotype, are sometimes also small and submicroscopic and can occur on any telomere (the end of a chromosome). The phenotypic changes are subtle. Subtelomeric deletions can be present in people with non-specific mental retardation and mild dysmorphic features, but also in the more severely affected people with multiple congenital anomalies.

Health Life Media Team

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