On which chromosome is the progeria located

Progeria counselor

Development of progeria

Premature aging, progeria, is based on genetic causes. The exact background for the occurrence of progeria has not yet been fully researched. However, not just one defect but several mechanisms are held responsible. Since the "normal" aging process is already very complex, the various diseases associated with premature aging are also considered to be very complex in their development.

Development of Hutchinson-Gilford progeria syndrome (HGPS)

Progeria in infancy differs from a “normal” aging process. Children with Hutchinson-Gilford progeria syndrome are not prone to Alzheimer's disease, cataracts, senile deafness, presbyopia or diabetes mellitus like "normal" aging people, and they do not have an increased tumor risk.

Hutchinson-Gilford progeria syndrome is presumably inherited as an autosomal dominant trait. Autosomal dominant means that the defect is on the autosomes, not on the sex chromosomes (gonosomes). As soon as there is a defect - in this case a defective allele (one of two existing gene copies) is sufficient - the corresponding change becomes apparent. Since the parents do not show these changes and those affected do not reach reproductive age, it is a new mutation or a spontaneous mutation.

Said spontaneous mutation affects the lamin A gene on chromosome 1. Lamines are proteins that form a chain structure and that, among other things, play an important role in the structure of the cell nuclear envelope. Lamin-A, however, as part of the protein chain, has a spelling mistake in the genetic code of progeria patients (the positions of the DNA bases thymine and cytosine are reversed), resulting in a modified protein (progerin). This process influences the function of the entire chain and makes it unstable. The cell nuclear envelope is weakened and the cell nucleus deforms. As a result, the body tissue is no longer able to regenerate.

In addition, telomeres seem to be responsible for aging. Telomeres are the end sections of the chromosomes - there is something like a clock of life there. Already after birth, the telomeres shrink and with each cell division they shorten a little. People with progeria have dramatically shortened telomeres.

Development of the Werner syndrome

Werner syndrome is presumably inherited as an autosomal recessive trait and is more common in relatives. Autosomal recessive means that the disease can only arise if the mother and father of the person affected are each carrier of the corresponding genetic change and both pass on the corresponding predisposition to the child. However, the parents themselves do not have to be ill. The defect is not on the sex chromosomes. In Werner syndrome, the RecQL1 gene on the short arm of chromosome 8 is affected. The defect intervenes in various processes and ultimately influences the repair mechanisms of damage to the genetic material. As a result, the mutation rate can increase and the telomeres shorten rapidly.

Christa Windmüller

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