4th March 2024

An 11-month-old female presents to the genetics clinic after a referral from the paediatric neurology clinic

An 11-month-old female presents to the genetics clinic after a referral from the paediatric neurology clinic. Her mother reports she was hypotonic at birth. Her development was unremarkable through the first five months of infancy. At seven months, her mother began to notice that her development had begun to halt, and she was no longer attaining her developmental milestones from now on. There were suggestions that her vision was deteriorating as she would not notice visual cues from her mother.

At nine months old, she began to develop generalised tonic-clonic seizures, accompanied by generalised regression in all domains of her development. She has an exaggerated startle reflex. Neurological examination shows global weakness with hyperreflexia and clonus. Ophthalmological examination shows bilateral cherry red spots.

Which of the following gene mutations likely cause her underlying diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.