He Williams syndrome (SW) is a developmental disorder of genetic origin that is associated with a characteristic profile Of physical and cognitive affectations (Galaburda et al., 2003).
Specifically, Williams syndrome, at the clinical level, is characterized by 4 cardinal points: 1) features and facial features Atypical, 2) generalized delay of the psychomotor development and specific neurocognitive profile, 3) cardiovascular alterations and 5) possibility of development of Hypercalcemia (Casnelles and Pérez Jurado Field, 2010).
Although Williams syndrome is considered a rare disease, there are thousands of people affected worldwide (Williams Syndrome Association, 2014).
As for the diagnosis, the clinical examination usually provides the necessary findings for its establishment, however, to rule out other Pathologies and false positives, a genetic study is usually initiated through several techniques (Antonell et al., 2006).
On the other hand, there is neither a cure for Williams syndrome nor a standard treatment protocol, so much of the interventions Therapeutic approaches to regulate medical complications (National Institute of Neurological Disorders and Stroke, 2015).
In addition, it will be essential to include early attention , Individualized special education and neuropsychological stimulation (González Fernández and Uyaguari Quezada, 2016).
Characteristics of Williams syndrome
Williams syndrome is a developmental disorder that can significantly affect different areas (Genetics Home Reference, 2016).
Generally, this pathology is characterized by the presence of atypical facial features or cardiovascular alterations, intellectual disability Learning, and some Personality traits (Genetics Home Reference, 2016).
Thus, the first patient with Williams syndrome was described by the doctor Guido Fanconi , In a clinical report of 1952 (Campo Casanelles and Pérez Jurado, 2010).
However, it was the cardiologist Joseph Williams who, in 1961, accurately identified this pathology, while it was described by German Beuren (García-Nonell et al., 2003).
Because of this, Williams syndrome is named by both authors (Williams-Beuren syndrome), or simply the first (Casanelles Field and Pérez Jurado, 2010).
Although, until a few years ago, the identification of the pathology was made based on the characteristics Phenotypic (Galaburda et al., 2003), In 1993, Edward et al. Found a genetic anomaly on chromosome 7q 11.23 as the etiological cause of this pathology (García-Nonell et al. 2003).
Although the Williams syndrome condition involves a wide variety of secondary medical complications, it does not present A high mortality rate. In many cases, affected individuals are able to achieve an independent functional level (National Institute Of Neurological Disorders and Stroke, 2015).
About us
Williams syndrome is considered a rare or rare genetic disorder (Herdon, 2016).
The Williams Syndrome Association (2016), among other institutions, have estimated that Williams syndrome has a prevalence of approximately 1 Case for every 10,000 people around the world.
Specifically, it has been identified that in the United States there may be around 20,000 or 30,000 affected (Wiliams Syndrome Association, 2016).
As for the distribution of pathology by sex, there are no recent data that indicate a higher prevalence in some of them, nor is it Have identified differences between geographic regions or ethnic groups (González-Fernández and Uyaguari Quezada, 2016).
On the other hand, we also know that Williams syndrome is a sporadic medical condition, although some cases of transmission have been described (Casanelles and Pérez Jurado Field, 2010).
Signs and symptoms
Williams syndrome, like other pathologies of genetic origin, presents a clinical course characterized by a multisystemic affection.
Many authors, such as González Fernández and Uyaguari Quezada (2016), describe the clinical spectrum of Williams syndrome categorized in several areas: Biomedical characteristics, psychomotor and cognitive characteristics, psychological and behavioral characteristics, among others.
Biomedical Characteristics
The physical involvement present in Wiliams syndrome is diverse, among the most frequent clinical findings we can observe (Campo Casanelles y Pérez Jury, 2010):
- Generalized delay of growth: Already during the gestation a delayed or slowed development can be detected. Children Affected by Williams syndrome are usually born with a reduced weight and height. In addition, once the adult stage is reached, the overall height is usually Lower than the general population, about 10-15 cm.
- Atypical facial features: Facial alterations are one of the most characteristic clinical findings in this syndrome. In Affected individuals, we can observe a significantly narrow forehead, marked skin folds in the Eyelid fissure , Strabismus, iris Starry, short and flattened nose, prominent cheekbones and a smaller chin than usual.
- Musculoskeletal disorders: In the case of alterations related to the development of muscles and bones, it is possible To observe the presence of reduced muscle tone and strength, joint laxity, scoliosis, contractures, among others. At the visual level, one can observe Posture characterized by drooping shoulders and semi-flexed lower extremities.
- Hearing impairment: Although significant anomalies or malformations are not found in the auditory hall, In all cases, an increase in auditory sensitivity develops. Affected individuals have to perceive or experience certain sounds Like annoying or painful.
- Skin disorders: The skin usually presents little elasticity, so it is possible to observe early signs of aging. In addition, it is possible that hernias develop, especially in the inguinal and umbilical region.
- Cardiovascular disorders: The different abnormalities in the heart and blood vessels, constitute the most Significant, since they may endanger the survival of the affected person. Among cardiovascular anomalies, some of the most common are Supravalvular aortic stenosis, stenosis of the pulmonary branches, aortic valve stenosis. All these alterations, at the clinical level, Can affect other vascular territories and even the brain, due to the development of hypertension.
- Disorders of the genitourinary system: Anomalies related to renal function and bladder are very common. In addition, Accumulation of calcium (nephrocalcinosis), urinary urgency, or Nocturnal enuresis .
Psychomotor and cognitive characteristics
At the cognitive level, the most significant characteristics are constituted by a generalized delay of the acquisition of motor skills, delay Intellectual impairment and various alterations related to visual perception.
- Psychomotor alterations: Several alterations related to problems of balance, coordination, that are due Mainly to the presence of musculoskeletal anomalies and that will cause, among other things, a delay in the acquisition of gait, Motricity, etc.
- Cognitive Features: It is possible to find a moderate mental retardation, the CI Typical of those affected usually range from 60 to 70. In addition, regarding the specific areas that are affected, there is a clear asymmetry: in addition to psychomotor coordination, the perception and Visual integration, is often clearly affected, while areas such as language tend to be more developed.
- Language features: In the earliest stages, there is usually a delay in the acquisition of language skills, However, it usually recovers around 3-4 years. Children with Williams syndrome, usually have good expressive communication, are able to Using contextualized vocabulary, correct grammar, eye contact, facial expressions, etc.
- Psychological and behavioral characteristics: One of the most significant findings in Williams syndrome, is the exceptional Social behavior of those affected. Although anxious crises or excessive worries may occur in some cases, they are very empathic and sensitive.
Causes
Recent research has indicated that the cause of Williams syndrome is found in various genetic alterations on chromosome 7 (National Organization for Rare Disorders, 2006).
The chromosomes carry the genetic information of each person and are located in the nucleus of the cells of the organism.
In humans, we can find 46 chromosomes that are distributed in pairs. These are numbered from 1 to 23, except for the last couple constituted By the sex chromosomes, denominated XX in the case of the XY women in the case of the men. Thus, within each chromosome there may be infinity Of genes.
Specifically, the anomalous process identified in Williams syndrome is a microcelection or rupture of a DNA molecule that confirms this chromosome. Typically, this type of error occurs in the development phase of the Gametes Male or female (Orphanet, 2006).
Genetic anomalies are found in the area 7q11.23, in which more than 25 different genes have been identified related to the clinical pattern Characteristic of this pathology (National Organization for Rare Disorders, 2006).
Some of the genes, such as Clip2, ELN, GTF21, GTF2IRD1 or LIMK1, are absent in those affected. The loss of ELN is related to the Connective tissue, cutaneous and cardiovascular abnormalities (Genetics Home Reference, 2016)
On the other hand, some investigations indicate that the loss of the genes Clip2, GTF2I, GTF2IRD1 and LIMK1, can explain the alterations in the processes Visuoperceptives, behavioral phenotype, or cognitive deficits (Genetics Home Reference, 2016).
In addition, specifically, the GTF2IRD1 gene appears to play a prominent role in the development of atypical facial features. For its part, the NCF1 gene Appears to be related to a high risk of developing hypertension (Genetics Home Reference, 2016).
Diagnosis
Until the last years, the diagnosis of Williams syndrome was made exclusively based on the observation of the phenotypic characteristics (Facial alterations, intellectual disability, specific cognitive deficits, among others) (Galaburda et al., 2003).
However, the diagnosis of Williams syndrome is currently performed at two points: analysis of clinical findings and genetic studies Of confirmation (González Fernández and Uyaguari Quezada, 2016).
Thus, clinical diagnosis usually includes:
- Exploration and physical and neurological assessment.
- Analysis of growth parameters.
- Exploration of cardiorespiratory system.
- Nephrourological exploration.
- Analysis of calcium levels in urine and blood.
- Ophthalmologic analysis.
On the other hand, the genetic analysis is used to confirm the presence of genetic alterations compatible with the syndrome of Williams, between the The most common tests are the Fluorescent in situ hybridization (FIHS).
After extraction of a blood sample, the In Situ Hybridization technique is performed by labeling DNA probes that are detected under a fluorescent light (González Fernández and Uyaguari Quezada, 2016).
Treatment
There is no specific treatment for Williams syndrome, however, this pathology is associated with multiple complications in different Organs, so that medical interventions will be directed towards the treatment of these.
Authors González Fernández and Uyaguari Quezada (2016), emphasize that, all interventions must have a marked multidisciplinary character, that gives Fit to the treatment of the symptomatic variety characteristic of this syndrome.
In addition, these also indicate various therapeutic measures depending on the affected area:
- Medical area: In this case, medical complications such as cardiac abnormalities or musculoskeletal malformations, Usually require treatment based primarily on drug delivery and surgical procedures. In the treatment of symptoms Physicians usually involve medical professionals from different areas (pediatricians, cardiologists, ophthalmologists, etc.).
- Neuropsychological area: Cognitive deficits such as visuoperceptive impairment or linguistic delay, should be Early stages. The Cognitive stimulation And rehabilitation, will be a determining factor in the achievement of an autonomous life during the age Adult
- Psychological area: Although those affected by Williams syndrome usually have a good social functioning, in some cases Have to show excessively anxious behaviors and to develop persevering behaviors or phobias, therefore, in these cases it will be fundamental to put in A psychological approach, through various strategies that are effective to minimize these problems or difficulties.
References
- Antonell, A., del Campo, M., Flores, R., Campuzano, V., & Pérez-Jurado, L. (2006). Willims syndrome: clinical aspects and molecular basis. Rev Neurol, 69-75.
- Cleveland Clinic. (2013). Williams Syndrome. Obtained from Cleveland Clinic.
- Of the Field Castenelles, M., & Pérez Jurado, L. (2010). Follow-up protocol in Williams syndrome. Spanish Association of Pediatrics, 116-124.
- Galaburda, A., Holinger, D., Mills, D., Reiss, A., Korenberg, J., & Bellugui, U. (2003). Williams syndrome. A summary of cognitive findings, Electrophysiological, anatomofunctional, microanatotic and genetic. Rev Neurol, 132-137.
- García-Nonell, C., Rigau-Ratera, E., Artigas-Pallarés, J., García Sánchez, C., & Estévez-González, A. (2003). Williams syndrome: memory, functions Visuospatial and visuoconstructive functions. Rev Neurol, 826-830.
- González Fernández, N., & Uyaguari Quezada, M. (2016). Williams syndrome.
- Herndon, J. (2016). What Is Williams Syndrome? Retrieved from HealthLine.
- NIH. (2015). Williams Syndrome. Retrieved from the National Institute of Neurological Disorders and Stroke.
- NIH. (2016). Williams Syndrome. Retrieved from the Genetics Home Reference.
- NORD. (2006). Williams Syndrome. Retrieved from the National Organization for Rare Disorders.
- Orphanet. (2006). Williams Syndrome. Obtained from Orphanet.
- Williams Syndrome Association. (2016). WHAT IS WILLIAMS SYNDROME? Obtained from Williams Syndrome Association.