Using the Finnish babies and their families, researchers discovered the gene mutation responsible for hydrolethalus syndrome in the Finnish population. The gene, called HYLS-1, is on chromosome 11. Research suggests that the genetic mutation is inherited in an autosomal recessive pattern.
Symptoms of Hydrolethalus Syndrome
Hydrolethalus syndrome consists of a group of distinctive birth defects, including:
Severe hydrocephalus (excess fluid in the brain)Extremely small lower jaw (called micrognathia)Cleft lip or cleft palateA malformed respiratory systemCongenital heart defectsExtra fingers and toes (called polydactyly), especially a duplicated big toeMalformation of the brain, including missing structures
Diagnosis of Hydrolethalus Syndrome
Many babies with hydrolethalus syndrome are recognized before birth by prenatal ultrasound. The hydrocephalus and brain malformation suggest the diagnosis. Close examination of the fetus by ultrasound, or the baby at birth, is needed to rule out similar syndromes such as Meckel syndrome, Trisomy 13, or Smith-Lemli-Opitz syndrome.
Outlook
Often the baby with hydrolethalus syndrome is born prematurely. About 70% of babies with the syndrome are stillborn. Those born alive do not survive for very long.
