Hydrolethalus syndrome is a serious disorder that affects how a baby’s face, limbs, heart, and other vital organs develop.
This condition causes severe problems in the brain, including an abnormal buildup of fluid around it. Babies with this syndrome might have extra fingers or toes, heart defects, and issues with their airways and lungs. Doctors can detect these problems using ultrasound scans during pregnancy. Sadly, Hydrolethalus syndrome is usually fatal, meaning most babies with this condition do not survive for long after birth. In rare cases, some infants have lived for a few months, but most either don’t survive childbirth or pass away shortly after being born.
Hydrolethalus syndrome is caused by pathogenic (disease-causing) variants in the HYLS1 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background.
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Revised October 2023
