Genetic defect of rare dwarfness decoded

Rare genetic defect decrypted as the cause of extreme dwarfism

08/08/2011

An international research team has deciphered the underlying genetic defect of a particularly rare form of dwarfism. However, despite the current research successes, there are no chances of recovery for the patients, as the effects of the genetic defect can not be remedied, explained the director of the University Clinic for Women's and Children's Medicine in Leipzig, Professor. Wieland Kiess.

According to the University of Leipzig, it is estimated that only about 25 people worldwide suffer from the so-called Seckel syndrome. The only two patients in Germany are Prof. Dr. med. Wieland Kiess looks after. The cause of the extremely rare disease is a genetic defect that an international team of researchers under Turkish leadership has now riddled, the scientists report in the current issue of the journal „ Nature Genetics“.

Seckel syndrome especially rare form of dwarfism
Patients with Seckel's syndrome usually do not grow larger than one meter even in adulthood and have a very small head (microcephaly), which also blocks the growth of their brains and their mental development can be severely restricted (mental retardation). Other physical impairments such as malalignment of the hip (hip dysplasia) or malformations of the testes (cryptorchidism) are also often part of the disease. In most cases, the Seckel syndrome patients are often disabled and depend on outside help for a lifetime. The disease was discovered in 1967 by Helmut Paul George Seckel and Rita G. Harper. The cause of the particular form of dwarfism is a genetic defect whose exact mode of action has remained a mystery. However, the international research team with the participation of scientists from the University of Leipzig has now been able to decipher the effect of the genetic defect.

Gene defect causes disruption in cell division
According to the researchers in the journal „Nature Genetics“, causes the genetic defect of the Seckel syndrome in the context of cell division disorders in repair of the Erbbotschaft. Although DNA is more likely to be damaged during the cell division process, biochemical repair mechanisms work well in healthy people. Kiess. In the Seckel syndrome patients, however, the complex repair mechanisms are significantly disturbed. The errors in the genetic information can not be corrected and massive health problems are the result. Fortunately, the previously identified genetic defects on chromosomes 3, 14 and 18 are rather rare and only if the DNA of both parents contains a chromosome of the disease threatens the children the extremely rare form of dwarfism (autosomal recessive inheritance).

No hope for cure for affected patients
Although the international research team has succeeded in deciphering the genetic defect in Seckel syndrome, the current results are no reason for hope for those affected. The patient suffering from this particular form of dwarfism could not be helped, explains Kiess. Since the effects of the genetic defect can not be resolved, there is no chance of a successful therapy, according to the expert. In addition to the extremely rare Seckel syndrome, for example, genetic disorders such as the Hallermann-Streiff syndrome and Rubinstein-Taybi syndrome have a significantly reduced growth and numerous other physical or mental impairments result. For the physicians, the care of patients is often extremely difficult because there are no ways to cure the disease but only therapeutic measures to alleviate the symptoms. (Fp)

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Image: Gabi Schoenemann