A rare genetic disorder characterised by growth delays before and after birth (prenatal and postnatal growth retardation), short stature, a varying degree of mental deficiency, and distinctive facial features that typically become more pronounced with age.
It is a deletion in chromosome 7.
The deleted section contains approximately 25 genes. The gene elastin, which gives elasticity to the blood, is one of the missing genes. Without it, heart defects and disorders of the circulatory system are common.
It affects males and females in equal numbers and infants of any race may be affected.
Vitamin D
Hypercalcemia (high calcium levels) which is associated with some cases of Williams syndrome, may occur because of an abnormal sensitivity to vitamin D.
Talk to your medical doctor before taking vitamin D supplements for growth and development.
Cause
Most cases of Williams syndrome appear to occur spontaneously (sporadically) for unknown reasons. However, some familial cases of the disorder have also been reported. Ongoing research indicates that sporadic and familial Williams syndrome result from deletions of genetic material from adjacent genes (contiguous genes) located on the long arm (q) of chromosome 7 (7q11.23). This chromosomal region has been designated “Williams-Beuren Syndrome chromosome region 1” (WBSCR1).
Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Pairs of human chromosomes are numbered from 1 through 22, and an additional 23rd pair of sex chromosomes which include one X and one Y chromosome in males and two X chromosomes in females. Each chromosome has a short arm designated “p” and a long arm designated “q”. Chromosomes are further sub-divided into many bands that are numbered.
For example, “chromosome 11p13” refers to band 13 on the short arm of chromosome 11. The numbered bands specify the location of the thousands of genes that are present on each chromosome.
According to investigators, 28 genes within the 7q11.23 chromosomal region may play a causative role in Williams syndrome including those known as the ELN (elastin) gene, the LIMK1 (or LIM kinase-1) gene, and the RFC2 (replication factor C, subunit 2) gene. The LIMK1 gene is believed to be involved with visual-spatial problems associated with Williams syndrome.
In familial cases, Williams syndrome is inherited as an autosomal dominant trait. Genetic diseases are determined by two genes, one received from the father and one from the mother.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease.
The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.
Difficult to concentrate/difficulty in concentrating/memory problems and/or learning difficulties and/or a short attention span and are easily distracted?
Friendly, outgoing, talkative manner of speech?
Like and/or are fond of music?
Don’t like to be handled?
Flared eyebrows
Puffy eyes?
A star-like (stellate) pattern in the iris of the eye may be apparent in about 50 percent of children with this disorder?
Sensitive to sound and may overreact to unusually loud or high-pitched sounds (hyperacusis)?
Experience inward deviation of the eyes (esotropia) and farsightedness (hyperopia)?
Vertical skin fold on the inner corners of the eyes (epicanthal folds)?
Unusually short eyelid folds (palpebral fissures)?
Broad nasal bridge with nostrils that flare forward (anteverted nares)?
Prominent ears?
Full cheeks?
Unusually long vertical groove in the centre of the upper lip (philtrum)?
Thick and puffy lips?
Large mouth that is usually held open?
Speech delays?
Round face?
Small pointed chin?
Small lower jaw (mandible)?
Dental abnormalities may also occur including abnormally small, underdeveloped teeth (hypodontia) with small, slender roots?
Small teeth (microdontia), and upper and lower teeth that do not meet properly (malocclusion)?
Unusually hoarse voice?
Feed poorly?
Heart (cardiac) defects, abnormally increased levels of calcium in the blood during infancy (infantile hypercalcemia), musculoskeletal defects, and/or other abnormalities?
Depression of the breastbone (pectus excavatum)?
Breast development and menstruation may occur earlier than expected?
Cardiac defects may include obstruction of proper blood flow from the lower right chamber (ventricle) of the heart to the lungs (pulmonary stenosis)
Abnormal narrowing above the valve in the heart between the left ventricle and the main artery of the body (supravalvular aortic stenosis)?
Short of breath and/or breathing difficulties (whether after exercise or not) and/or wheezing?
Regular and reoccurring chest infections?
Heart palpitations and/or irregular heartbeats?
Abnormal side-to-side or front-to-back curvature of the spine (scoliosis or kyphosis)?
Inward turning of the great toe toward the other toes (hallux valgus)?
Skeletal and joint abnormalities may result in an abnormal manner of walking (awkward gait) and/or bone and joint movement problems and/or abnormally exaggerated reflexes (hyperreflexia)and/or difficulty using arms and/or body and/or legs and/or lack of stamina and/or walking difficulties and/or crawling difficulties and/or rolling over difficulties?
One find passing stools difficult (can be painful) and constipated?
Abnormalities of the kidneys/Pain in pelvis area and/or lower back and/or intense pain in the back or side (or moving pain from back to side) or in groin area?
High blood pressure (hypertension) is also common in adults?
The following disorders may be associated with Williams Syndrome as secondary characteristics.
They are not necessary for a differential diagnosis:
Pulmonary artery stenosis is a rare congenital heart defect characterized by unusual narrowing of the vessel that carries blood from the right ventricle of the heart to the lungs (pulmonary artery). This defect usually occurs in association with other heart defects, such as septal defects and/or supravalvar aortic stenosis. Symptoms may include unusual heart sounds (murmurs), difficulty breathing, chest pain, and, in severe cases, congestive heart failure.
Ventricular septal defects are heart defects that are present at birth (congenital) and can occur in any portion of the ventricular septum. The size and location of the defect determines the severity of the symptoms. Small ventricular septal defects can close on their own or become less significant over time. Moderately-sized defects can cause congestive heart failure resulting in an abnormally rapid rate of breathing (tachypnoea), wheezing, an unusually fast heartbeat (tachycardia), enlargement of the liver, and/or failure to thrive. Large ventricular defects can cause life-threatening complications during infancy.
Idiopathic infantile hypercalcemia is characterized by the elevation of blood calcium levels in a new born for which there is no apparent cause (idiopathic). Symptoms may include loss of appetite (anorexia), irritability, confusion, weakness, easy fatigability, and/or abdominal and muscle pain.
Some studies in the medical literature question whether idiopathic infantile hypercalcemia is a separate disorder from Williams Syndrome or if it is a variant of the same disease.
Infants with this form of the disease do not have the characteristic facial features or heart defects that are associated with Williams Syndrome.
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Detailed Information
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