hidea syndrome hidea syndrome hidea syndrome is a syndrome characterised by hypotonia, hypoventilation, intellectual disability, dysautonomia, epilepsy, and eye abnormalities. it is caused by the mutation of the p4htm gene on chromosome 3. hidea syndromehidea syndrome is inherited via an autosomal recessive manner.causesmutation in p4htm gene presentation this syndrome causes intellectual disability and affects the eyes, musculoskeletal system, and face. eyes strabismus difficulty fixing the eyes on an object face facial features gradually become coarser during childhood. musculoskeletal system hypotonia planovalgus contractures in elbow joints interphalangeal joint hypermobility other associated features include hypoventilation, obstructive and central sleep apnea and dysautonomia. genetics this condition is caused by mutations in the prolyl 4-hydroxylase, transmembrane (p4htm) gene. this gene is located on the short arm of chromosome 3 (3p21.3). the inheritance of this condition is autosomal recessive. diagnosis the diagnosis may be suspected on clinical grounds. it is made by sequencing the p4htm gene. management there is presently no curative treatment. management is supportive. epidemiology the prevalence is not known but this is considered to be a rare disease. only 12 patients have been reported to date. history this condition was first described in 2014. the causative mutation was discovered in 2019.