He Prader-Willi syndrome ( SPW ) Is a multisystemic disease that has a congenital genetic origin (National Organization for Rare Disorders, 2012). It is a complex disease affecting appetite, growth, metabolism, behavior and / or cognitive function (USA Prader-Willi Syndrome Association, 2016).
At the clinical level, during childhood, this disease is characterized by the presence of various medical findings such as muscle weakness, altered eating or generalized developmental delay (Genetics Home Reference, 2016).
In addition, at the cognitive and behavioral level, a good part of the individuals affected by the Prader-Willi syndrome present a deterioration or delay Moderate intellectual, which is accompanied by various problems of learning and behavior (Genetics Home Reference, 2016).
Although Prader-Willi syndrome is considered a rare or uncommon disease, numerous studies indicate that it is one of the most common pathologies Frequent in the genetic area (USA Prader-Willi Syndrome Association, 2016).
The diagnosis of this disease is based primarily on clinical findings and complementary genetic testing (Foundation for Prader-Willi Research, 2014).
Regarding treatment, a cure for Prader-Willi syndrome has not yet been identified, so that the therapeutic approach is oriented toward the Treatment of symptoms and complications, with obesity being the medical finding that poses a greater threat to those affected (National Institutes of Health, 2016).
Thus, in relation to prognosis and quality of life, both will depend on the severity of the associated medical problems and behavioral disorders or Cognitive factors that can be developed (Campubrí-Sánchez et al., 2006).
Characteristics of Prader-Willi syndrome (SPW)
Different clinical reports indicate that Prader-Willi syndrome (SPW) was initially described by J. L. Down, in 1887, after diagnosis To one of his patients of"polysarcia"(Solà-Aznar and Giménez-Pérez, 2006).
However, it was Dr. Prader, Labhart and Willi who, in 1956, described another 9 cases and named this pathology (Rossel-Raga, 2003).
In addition, the characteristics and diagnostic criteria of Prader-Willi syndrome were systematized by Holm et al. (Campubrí-Sánchez et al. 2006).
Prader-Willi syndrome is a congenital genetic disorder, that is, it is a pathology that is present from the moment of birth and Will affect the individual throughout his life if there is no curative therapeutic intervention (Spanish Association Prader-Willi Syndrome, 2016).
This pathology presents a complex clinical course, characterized by numerous medical manifestations (Campubrí-Sánchez et al., 2006).
Although, Phenotype Of Prader-Willi syndrome is more precisely known (Campubrí-Sánchez et al., 2006), it has been in recent years 25 years, when there has been significant progress in the analysis and understanding of this disease (Solà-Aznar and Giménez-Pérez, 2006).
The expression of Prader-Willis syndrome is diverse, tends to affect multiple systems and structures, most of which are related Alterations with a Hypothalamic dysfunction (Poyatos et al., 2009).
He Hypothalamus , Is a neurological structure that plays an essential role in the control of type functions Homeostatic : The regulation of hunger, Thirst, sleep-wake cycles or regulation of body temperature (Rosell-Raga, 2003).
In addition, the hypothalamus releases different hormones into various glands: growth, sex, thyroid, etc. (Rosell-Raga, 2003).
Finally, it should be noted that Prader-Willis syndrome may also be referenced in the medical and experimental literature with other terms Such as Prader-Labhart-Willi syndrome or the PWS (National Organization for Rare Disroders, 2012).
In addition, other synonyms are: Labhart Willi Syndrome, Praser Labhart Willi Fancone Syndrome, or Hipogenital Dystrophy Syndrome (del Barrio del Campo Et al., 2008)
About us
Prader-Willi syndrome (PWS) is a rare genetic disease (Orphanet, 2007).
The term Rare Disease (ER), is used to refer to those pathologies that are uncommon or that few people have it (Spanish Association Prader-Willi Syndrome, 2016).
Currently, it is estimated that Prader-Willi syndrome is a pathology with an approximate frequency of 1 case per 10,000-30,000 people throughout the Genetics Home Reference, 2016.
On the other hand, as regards the distribution by sex, it has been observed that this pathology affects men and women equally, besides Associated with ethnic groups or geographic regions (National Organization for Rare Disroders, 2012).
In addition, Prader-Willi syndrome is considered the leading cause of obesity of genetic origin (Poyatos et al., 2009).
Signs and symptoms
At the clinical level, Prader-Willi syndrome has traditionally been associated with neonatal hypotonia, Hypogonadism , Hyperphagia, obesity, short stature, Generalized developmental delay, moderate intellectual disability, atypical facial appearance, and different behavioral disturbances (Poyatos Et al., 2009).
In spite of this, the clinical expression of this pathology is very heterogeneous and varies significantly among the affected individuals (Poyatos et al. 2009).
In addition, the characteristic signs and symptoms of Prader-Willi syndrome vary with biological development, so we can observe Different clinical findings in the fetal and neonatal period, lactation period or early childhood, school stage and, finally, the adolescent stage (Del Barrio del Campo et al., 2008).
In a systematic way, José A. del Barrio del Campo and collaborators (2008), describe in detail the most characteristic alterations of the area Biomedical, psychomotor, cognitive and behavioral:
Biomedical manifestations
The most characteristic physical signs and symptoms include alterations such as; Hypotonia, malformations or musculoskeletal deformities, weight and Short or low stature, excess appetite, obesity, hypogonadism, Sleep disturbances , Respiratory disorders, atypical easy traits, alteration In the regulation of body temperature, among others.
- Hypotonia : Presence or development of reduced muscle tone. The muscle flaccidity in this pathology is especially accentuated in The neck and the trunk, especially in the neonatal stage and the first months of life. Thus, with biological development, muscle tone tends to improve.
- Musculo-skeletal deformities or malformations : In this case, it is frequent to observe the development of scoliosis Or deviation of the Column, a poor alignment of the lower limbs (genu valgus) or the presence of flat feet. In addition, other types of Congenital anomalies such as reduced foot and hand size, hip dysplasia, presence of six fingers, among others.
- Low weight and size : Especially at birth, both the height and weight of the affected child is less than expected For their development and sex. Although standard values can be reached in adulthood, the slow rate of growth tends to Adult values of height and weight.
- Excess appetite and obesity: It is common to see in people suffering from Prader-Willi syndrome an insatiable appetite, Characterized by an obsession or fixation by food. Due to the intake of large quantities of food, the affected have to develop Obesity and other associated medical complications, such as Type II diabetes mellitus .
- Hypogonadism: Also the presence of genital alterations are frequent. Specifically, hypogonadism or partial development of The external genitalia is very frequent. In most cases, pubertal development fails to reach final or adult stages.
- Respiratory disorders and disturbed sleep-wake cycles: Snoring, increased frequency or stops Respiratory problems usually recur during the sleep phases. Thus, the affected have to present diverse alterations related to Fragmentation, delayed sleep or the presence of periodic awakenings.
- Atypical facial features: Abnormalities and musculoskeletal malformations can also affect the cranio-facial features. Is Possible to observe a narrow skull, Eye strabismus , Skin and hair little pigmented, small mouth and thin lips, malformations of teeth, etc...
- Alteration of the regulation of body temperature: People with Prader-Willi syndrome often have problems Related to the regulation of body temperature, in addition another significant finding is the high resistance to pain.
Psychomotor and cognitive manifestations
Psychomotor manifestations
Due to the presence of musculo-skeletal malformations and reduced muscle tone, the development Psychomotor is going to be slower, affected to all areas.
Those affected usually present difficulties to carry out any type of activity that Requires one or more motor runs.
Cognitive Manifestations
In terms of cognitive limitations, most of those affected have an intellectual disability Light or moderate.
In addition to this, they usually present some specific areas more affected as the sequential processing of the information, the Recent or short-term memory, resolution of arithmetic problems, auditory processing of verbal information, alteration of attention and Concentration and presence of cognitive rigidity.
On the other hand, language is another area that is significantly affected in individuals with Prader-Willi syndrome. They often Delays in the acquisition of phonological skills, poor vocabulary, alteration of grammatical construction, among others.
Behavioral Manifestations
Behavioral problems and alterations are another of the typical findings that can be observed in Prader-Willi syndrome, usually having Vary depending on the age or the maturational stage in which the person is affected, however, some of the most Common are:
- Tongs Or irritability.
- Poor social interaction.
- Obsessive disorders.
- Behaviors of aggressiveness.
- Psychotic signs and symptoms.
Current research has indicated that behavioral disturbance tends to increase with age and, therefore, to aggravate, Social, family and emotional areas in general (Rosell-Raga, 2003).
Causes
As we have pointed out in several paragraphs above, Prader-Willi syndrome has a genetic origin.
Although there is currently considerable controversy about the specific genes responsible for this pathology, all data show that the alteration Etiology is located on chromosome 15 (Mayo Clinic, 2014)
Throughout the genetic study of this pathology, several have been the contributions. Burtler and Palmer (1838) detected the presence of anomalies in the Long arm of Chromosome 15 From the paternal parent, while Nicholls (1989) observed that in other cases the disorder was related to Chromosomal alterations from the mother (Rosell-Raga, 2003).
Apart from this, the most accepted theory about the origin of this pathology is the loss or inactivation of several genes of paternal expression that are Are located in the 15q11-13 region of chromosome 15 (Poyatos et al., 2009).
Diagnosis
The diagnosis of Prader-Willi syndrome, has two basic components, the analysis of clinical findings and genetic testing.
With regard to the detection of signaling signs and symptoms, both in babies and older children, it will be essential to make a history Detailed medical, individual and family. Likewise, a physical and neurological examination is also essential.
If, based on these procedures, there is a diagnostic suspicion, it will be necessary to prescribe several complementary tests to determine the Presence of alterations and genetic abnormalities.
Specifically, around 90% of the cases are definitively diagnosed through DNA methylation And other additional tests (National Organization for Rare Disorders, 2012).
In addition, it is also possible to perform a prenatal diagnosis of this medical condition, mainly in families with a previous history of Prader-Willi syndrome.
Specifically, the test amniocentesis Allows to extract samples of embryo for the accomplishment of the genetic examinations (National Organization for Rare Disorders, 2012).
Treatment
There is currently no cure for Prader-Willi syndrome. As in other rare diseases, treatments are limited to control Symptomatology and the improvement of the quality of life of the people affected.
However, one of the fundamental aspects will be nutritional and food control, since obesity is the main cause of morbidity and Mortality in this pathology.
On the other hand, the presence of cognitive and behavioral alterations will require the intervention of specialized professionals both in rehabilitation Cognitive as in the management of conduct disorder.
References
- AWSPW. (2016). What is Prader Willi Syndrome? Spanish Association Prader-Willi Syndrome .
- Campubrí-Sánchez, C., Gabau-Vila, E., Artigas-Pallarés, J., Coll-Sandiumenge, M., & Guitart-Feliubadaló, M. (2006). From clinical diagnosis to Genetic diagnosis of Prader-Willi and Angelman syndromes. Rev Neurol , 61-67.
- Of the District of the Field, J., Castro Zubizarreta, S., & San Román Muñoz, M. (2008). Chapter VIII. Prader-Willi syndrome.
- FPWR. (2016). About PWS . Retrieved from"Foundation for Prader-Willi Research".
- Mayo Clinic. (2014). Prader Willi Syndrome . Obtained from Mayo Clinic.
- NHI. (2016). Prader-Willi Syndrome . Retrieved from the Gnome Home Reference.
- NORD. (2012). Prader Willi Syndrome . Retrieved from the National Organization for Rare Disorders.
- Orphanet. (2007). Prader-Willi syndrome . Obtained from Orphanet.
- Poyatos, D., Camprubí, C., Gabau, E., Nosas, R., Villatoro, S., Coll, D., & Guitart, M. (2009). Prader Willi syndrome: study of 77 patients. Med Clin (Barc) , 649-656.
- Rosell-Raga, L. (2003). Behavioral phenotypes in Prader-Willi syndrome. Rev Neurol , 153-157.
- Rosell-Raga, L., & Venegas-Venegas, V. (2006). Autistic symptomatology and Prader Wili syndrome. Rev Neurol , 89-93.
- Solà-Aznar, J., & Giménez-Pérez, G. (2006). Comprehensive approach to Prader-Willi syndrome in adulthood. Endocrinol Nutr , 181-189.