Noonan syndrome: causes, symptoms and treatment
Much of what we are and how we are is given by our genetic code. The organization of our organism, the rhythm and the way our growth and physical development takes place ... and even a part of our intellect and our personality is inherited from our ancestors.
However, sometimes genes undergo mutations that, although sometimes can be innocuous or even positive, sometimes have severe repercussions that make it more difficult to develop and adapt to the environment of those who suffer from it. One of these genetic disorders is Noonan syndrome .
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Noonan's syndrome
Noonan syndrome is a relatively common genetic disorder that occurs in one out of every thousand or two thousand births, with a prevalence similar to that of Down syndrome. Is about a disease whose symptomatology can be highly variable depending on the case , but that is characterized by the presence of alterations and delays in the development, congenital cardiopathies, hemorrhagic diathesis and diverse morphological alterations.
The rhythm of growth in these children, although initially it seems normative, is severely slowed, and they usually have short stature and delays at the psychomotor level. This problems becomes especially evident in adolescence. Occasionally it is presented together with intellectual disability, although this is usually mild. Sensorially can present vision and hearing problems as strabismus or recurrent otitis.
At the morphological level, facial alterations such as ocular hypertelorism (the eyes are excessively separated from each other), drooping eyelids, low and rotated ears, short neck are seen from birth. It is also common that they present bony alterations in the form of deformity in the thoracic cage (which can appear in the form of a sunken chest in the area of the sternum or pectus excavatum or in its profusion or pectus carinatum).
One of the most dangerous symptoms is the presence in most patients of congenital heart diseases such as pulmonary stenosis or hypertrophic cardiomyopathy, as well as other vascular problems. Likewise, the presence of hemorrhagic diathesis is frequent in more than half of the patients, which means great difficulties in the coagulation that generates that much caution must be taken with the suffering of hemorrhages. They are also very easy to present bruises.
Although not so frequent can also have lymphatic problems that generate peripheral edema or even lungs and intestine. They also tend to have a higher risk of developing leukemia and other myeloproliferative problems.
In the genitourinary system may appear alterations such as cryptorchidism or not lowering of the testicles in males. This causes fertility problems in some cases. However, in the case of women, there are usually no alterations regarding their fertility.
Causes of the syndrome
Noonan syndrome is as we have already said a disorder of genetic origin, whose main cause has been found in the presence of mutations in chromosome 12. Specifically, Alterations appear as a mutation in the PTPN11 gene in half of the cases, although other genes can also cause it, such as KRAS, RAF1 or SOS1. These are genes that participate in the growth of cells and in their development, so that their alteration causes diverse alterations in different systems of the organism.
In general, it is considered an autosomal dominant disorder that can be inherited from parents to children (with more frequent transmission by the mother), although mutations that generate Noonan syndrome occur without any of the parents having it. transmitted or there are other cases in the family.
Treatments
There is currently no curative treatment for Noonan syndrome , being the existing treatments dedicated to alleviate the symptoms, prevent complications, intervene on structural and morphological anomalies, optimize their capacities and offer these people the best quality of life possible.
A multidisciplinary methodology is used for this purpose intervention of different professionals from both medicine and other sciences . The symptoms and alterations that those who suffer from this disease can be very variable, so that the treatment will depend on the type of alterations that they suffer.
In the Noonan syndrome, it is essential to regularly monitor and monitor the patient's health status, especially in the presence of probable heart disease.The problems of coagulation are not strange in this syndrome, so this fact must be taken into account when making possible surgical interventions. During the first years it may be necessary to use probes to feed the child. It is not strange that a treatment with growth hormone is used, so that the development of the minor is favored.
At the psychoeducational level, given the high prevalence of learning problems and / or intellectual disability, it is possible that it is required the use of psychostimulation , individualized plans in the school, reinforcement of the learning of basic skills of the daily life, logopedia and use of alternative and / or augmentative techniques of communication like the use of pictograms. It may also be necessary to practice physiotherapy to improve your motor skills.
Finally, genetic counseling should be taken into account once the subject reaches adolescence or adulthood due to the possibility of transmission of the disorder.
It may also be necessary to use psychological treatment for the subject, since feelings of inadequacy may appear, low self-esteem and depressive syndromes . Likewise, psychoeducation is necessary both for this and for the environment, and assistance to support groups could be useful.
Provided that possible complications are controlled, subjects with Noonan syndrome can have a standard of living equivalent to that of other people without this disorder. It is possible that some of the symptoms diminish with age as they become adults.
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Bibliographic references:
- Ali, O. & Donohoue, P.A. (2016). Noonan syndrome. In: Kliegman, R.M .; Stanton, B.F .; St. Geme, J.W. & Schor, N.F. (eds) Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier.
- Ballesta, M.J. and Guillén-Navarro, E. (2010). Noonan syndrome, Protoc.diagn.ter.pediatr .; 1; 56-63. Virgen de la Arrixaca University Hospital. Murcia.
- Carcavilla, A .; Santomé, J.L .; Galbis, L. and Ezquieta, B. (2013). Noonan syndrome. Rev.Esp.Endocrinol.Pediatr; 4 (suppl). University General Hospital Gregorio Marañón. Gregorio Marañón Health Research Institute. Madrid.
