Clinical MNGIE suspicion may arise from variable signs GI dysmotility, severe
cachexia, external ophthalmoparesis/ptosis, and (often subclinical) peripheral
neuropathy. As a next step, radiology assessment by brain MRI to detect diffuse
leukencephalopathy and, optionally, lactate peaks on MR spectroscopy.
Biochemical testing for thymidine (dThd) and/or deoxyuridine (dUrd) excess in
plasma and/or urine with optional assessment of thymidine phosphorylase (TP)
activity. Sequencing of the thymidine phosphorylase
(TYMP) gene should be performed to confirm the diagnosis
and to identify presymptomatic and asymptomatic mutation carriers in kindreds.
(clinical material from the patient reported in [9])