William (William-Beuren) syndrome

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BACKGROUND AND CLINICAL INFORMATION: Head  

Summary: William (William-Beuren) syndrome is clinically characterized by typical elfin face, dental problems, characteristic stenotic cardiovascular problems, and hypercalcemia. Although their mean IQ is only about 60, patients with William syndrome are associated with many cognitive strengths that are better than the matched controls. They also have a charactertic tendency to approach strangers indiscriminately. Geneticlly, it is associated with the deletion of elastin gene.

Physical Features/Clinical:

• Chemistry: Infantile hypercalcemia.

• Neurologic/Musculoskeletal: marked impaiment in fine motor movements, developmental delay, hypertonia in adults, joint contracture, gait abnormalities.

• Cardiovascular: supravalvular aortic stenosis that progress with age, peripheral pulmonic stenosis, or other arterial stenoses and hypertension. A rare complication is sudden death. Predisposing factors include coronary artery stenosis and severe biventricular outflow obstruction.

• Typical facial features (elfin facies): short upturned nose, puffy eyes or periorbital fullness, bitemporal narrowness, wide mouth, long filtrum, rominent ears, full cheekls, prominent lips, and small widely spaced teeth with frequent malocclusion and micrognathia.

• Herniation: umbilical and inguinal hernia, diverticula of bowel and bladder.

• Ocular: strabismus; lacy, stellate iris pattern.

• Others: Failure to thrive, feeding difficulties, hoarse voice, recurrent otitis media.

Behavioral:

• ADHD: Attention defecit hyperkinetic disorder.

• Anxiety.

• Hyperacusis (sensitivity to sound).

• Socially isolated and have great difficulties in maintaining friendship.

• Approach strangers indiscriminately: they usually appear charming, engaging, and chatty with stereotypic phases.

Neurocognitive:

• Mental retardation. Mean IQ is 60, with a characteristic profile of strength and weakness.

• Cognitive strength beyond the cognitively matched control group: including a good vocabulary, enhanced expressive language skills, and emotionally enriched narratives that are far better than those of the cognitively matched control group. These patients are typically chatty, with sterotypic phases and able to carry on the conversations that are not reflective of their intellectual deficits. Their personality is described as charming and engaging.

• Special strengths in discrimination of unfamiliar faces, immediate recall of unfamiliar faces, and perception of facial contours.

Genetics:

• Elastin (ELN) gene: Submicroscopic deletion of ELN gene at chromosome 7q11.23. Deletion in classic William’s syndrome is usually >500 kb. This is probably a contiguous gene syndrome. Deletion can be detected by cytogenetics or FISH.

• Physical features are probably secondary to the deletion of ELN gene.

GROSS PATHOLOGY: Head  

Small head circumference but the frontal regions, the limbic structures of the temporal lobe are proportionately spared.

HISTOPATHOLOGY AND IMMUNOHISTOCHEMISTRY: Head  

Autopsy reports are rare [Galaburda AM et al., 1994], abnormally oriented pyramidal neurons in visual cortex and ectopic neurons in subcortical white matter have been reported. Disproportional development of Heschl’s gyrus (in primary auditory cortex).

REFERENCES: Head

NeuroLearn NeuroHelp Neurodevelopmental Disorders  For Comment: KarMing-Fung@ouhsc.edu

Background    Neuroimaging    Histopathology & Immunohistochemistry    Reference