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Hydrolethalus Syndrome

What is Hydrolethalus Syndrome?

Hydrolethalus syndrome is an inherited disease that is characterized by severe craniofacial abnormalities and malformations of the limbs, heart, genitalia, respiratory system, and central nervous system (CNS). The most common CNS defects include hydrocephaly (abnormal buildup of fluid around the brain) with absent upper midline structures and a keyhole-shaped defect in the occipital bone (located at the back and lower part of the skull); however, other brain abnormalities can be seen. Other specific more common symptoms include preaxial polydactyly (extra digits), large septal defect (heart defect), and narrowing of the airway with irregular lobulation of the lungs. These malformations are considered lethal.

Today, HLS can be detected by an ultrasound scan around 13-15 weeks gestation primarily due to the brain malformation being visible, but cleft lip/palate, limb defects (especially double big-toe and/or club-feet), and heart defects may also be seen. Polyhydramnios is typically present in the later parts of the pregnancy.

How common is Hydrolethalus Syndrome?

The prevalence of Hydrolethalus syndrome in the general population is unknown. Among people of Finnish descent, approximately 1 in 20,000 individuals will be affected.

How is Hydrolethalus Syndrome treated?

At this time, there is no cure or treatment option for individuals with Hydrolethalus syndrome.

What is the prognosis for a person with Hydrolethalus Syndrome?

The prognosis for an infant with Hydrolethalus syndrome is poor. There have been rare cases where individuals with Hydrolethalus syndrome have lived for several months. However most individuals are either stillborn or die shortly after birth.

Resources

Online Mendelian Inheritance In Man

A database of human genes and genetic disorders authored by staff at Johns Hopkins University and published by the National Institutes of Health. It contains fairly scientific language.

Orphanet

A database of information on rare diseases, it was founded by the French Ministry of Health and the Institut National de la Santé et de la Recherche Médicale. It is now funded by the European Commission.

Other names for Hydrolethalus Syndrome

  • Salonen-Herva-Norio syndrome
  • Hydrolethalus syndrome 1
  • Hydrolethalus syndrome
  • HLS1
  • HLS
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