4th March 2024

A 4-year-old male presents to the genetics clinic after a referral from the neurologist

A 4-year-old male presents to the genetics clinic after a referral from the neurologist. After birth, his mother noted grit-like residue on his nappies shortly following birth, and his mother occasionally noted blood-stained urine in his nappies. He managed to sit upright at 12 months old but cannot walk. At age 2, he developed involuntary contractions of his limbs along with spasmodic arching of his back and writhing motion of his hands.

On examination today, he is hypotonic, and the writhing motion described by his mother is observed. Lacerations and deformities along his lower lip and several scars were noted along his fingers. His mother reports that he will frequently bang his head on the wall, and his scars were from the patient attempting to bite himself.

Given the likely diagnosis, which biochemical markers are likely abnormal?

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