Objective:

Ohtahara syndrome (OS) presents with suppression-burst pattern in the EEG in the early neonatal period.

PIGO mutations are among the class of glycosylation pathway disorders with phenotypical abnormalities, mental retardation and epilepsy. The objective is to study the clinical and neurophysiological features of OS associated with PIGO mutations.

Methods:

We report a case identified by early EEG and subsequent whole exome sequencing.

Results:

The infant girl was born at 35 weeks of gestation without consanguinity after a pregnancy complicated by polyhydramnios. Family history was negative for any neuro developmental disorders and epilepsy.

Examination findings included mild brachycephaly with hypertelorism and hypoplastic nails, two vessel umbilical cord, hypotonia and poor visual tracking. She developed seizures at second day.

Laboratory results showed elevated Alkaline phosphatase and Phosphorous levels. A long term video EEG showed suppression-burst pattern consistent with OS.

Brain MRI showed mild thinning of the posterior corpus callosum with mild colpocephaly.

Whole exome sequencing showed compound heterozygous state of H908Y and M451R variants in PIGO gene.

EEG subsequently evolved to a hypsarrythmia pattern without any infantile spasms, but refractory to medications.

Discussion:

PIGO mutations presents with a syndrome of high alkaline phosphatase, hyperphosphatemia, mental retardation and epilepsy. Only 4 families were described in literature with various mutations.

This case is a unique compound heterozygous mutation, presented with Suppression-Burst pattern in EEG characteristic of Ohatahara Syndrome with evolution to refractory epilepsy.