The HIDEA syndrome is a rare condition affecting a member of the prolyl 4-hydroxylase group of enzymes.

HIDEA is an acronym for key features:

(1) hypotonia (H), muscular and central

(2) hypoventilation (H), which may worsen during viral infections or pneumonia

(3) intellectual disability (I) and developmental delay

(4) dysautonomia (D), with constipation, abnormal temperature regulation and reduced sweating

(5) epilepsy (E)

(6) eye abnormalities (EA), which may include strabismus, achromic fundi, astigmatism, amblyopia, keratoconus)


Chromosome location: 3p21.31

Gene: P4HTM (prolyl 4-hydroxylase, transmembrane)


Inheritance: autosomal recessive


Additional findings:

(1) central and obstructive sleep apnea, which may be associated with sudden death

(2) variable obesity

(3) mild facial dysmorphism

(4) abnormal gait

(5) abnormal mitochondrial appearance and function in muscle biopsies

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