Infants with PEHO syndrome may become increasingly floppy (hypotonia) and lose control of their muscles. The muscles supporting the head become floppy and weak and rolling over, sitting, standing and walking are rarely accomplished. Oedema or swelling of the hands, feet and face is also a feature of PEHO syndrome which may be transient or permanent.
Another feature of PEHO syndrome is the occurrence of infantile spasms. These are a distinctive type of epileptic seizure characterised by brief, but often repetitive, muscle contractions usually involving the head, trunk, and extremities. They occur in association with a particular pattern on EEG examination known as hypsarrhythmia. More typical seizures also occur in PEHO syndrome and may begin from birth to 12 months. Infants with PEHO syndrome gradually lose their ability to see (optic atrophy). Visual fixation is either absent at birth or lost during the first months of life, leaving infants with wandering and upward-turning eyes. Learning difficulties (see entry Learning Disabilty) have also been associated with PEHO syndrome. These become apparent at an early stage and usually affect language skills.
At birth, neonates are severely floppy, have feeding difficulties and are very drowsy. Their appearance is characterised by an expressionless, pear-shaped face with narrow forehead, broad, puffy cheeks and receding chin. The nose is small and upturned and the mouth is constantly open with a curved upper lip. Earlobes are outward turning. Although the head size is normal at birth, it usually becomes smaller (microcephaly) during the first year and the face becomes narrower with time.