Mowat-Wilson syndrome

Also known as:  Hirschsprung disease-microcephaly-mental Retardation syndrome

Background

Mowat-Wilson syndrome (MWS) is a rare disorder which was first described in detail by Dr DR Mowat and Dr MJ Wilson in 1998, although individuals with the characteristics of  Hirschsprung’s diseaselearning disability and typical facial features, had been described by a number of doctors in the preceding 20 years. The syndrome affects both males and females and over 200 patients have been described in the literature.

Credits

Medical text written October 2004 by Contact a Family. Approved November 2004 by Professor J Clayton-Smith. Last updated October 2010 by Professor J Clayton-Smith, Consultant Clinical Geneticist, Genetic Medicine, St Mary’s Hospital, Manchester, UK.

What are the symptoms?

The major features of MWS are:

Typical facial features that include:

  • deep-set, widely-spaced eyes
  • thick eyebrows
  • characteristic ear shape with a turned-up ear lobe
  • broad nasal tip and short philtrum (the vertical central groove from the nose to the upper lip)
  • small open mouth with a highly arched palate
  • prominent chin.

Other features that have been observed in individuals with MWS include:

  • growth, and developmental delay – speech can be delayed or absent
  • failure to thrive in early life
  • congenital heart disease (see entry Heart Defects)
  • genitourinary anomalies
  • eye anomalies
  • white patches on the skin
  • agenesis of the corpus callosum, which is visible on a magnetic resonance imaging (MRI) scan.

A number of behavioural features have been seen in MWS, these include:

  • sociable, happy disposition
  • disrupted sleep pattern
  • tooth grinding and repetitive movements.

What are the causes?

Almost all patients with MWS have a mutation or a deletion of the ZEB2 gene (previously known as the ZFHX1B or SIP1 gene) on chromosome 2q22. Some patients have a chromosome rearrangement which interferes with the function of this gene.

How is it diagnosed?

Diagnosis of the Syndrome is made by recognition of the clinical features and identification of a ZFHX1B gene change. Diagnosis of the syndrome has been made on clinical grounds alone in a number of individuals without the gene mutation.

How is it treated?

MWS syndrome cannot be cured. Treatment is symptomatic (addressing the symptoms an individual experiences as part of the syndrome) and aimed at maintaining or improving quality of life.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
MWS is usually a sporadic disorder although there are rare families where two children have been affected. Genetic advice or counselling is therefore recommended for families.

Prenatal diagnosis
This may be possible in families with an affected child where a genetic change of ZEB2 has previously been identified in which a case of MWS exists.

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