RT Journal Article SR Electronic T1 MNGIE with lack of skeletal muscle involvement and a novel TP splice site mutation JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 125 OP 129 DO 10.1136/jmg.2003.013789 VO 41 IS 2 A1 K Szigeti A1 L-J C Wong A1 C-L Perng A1 G M Saifi A1 K Eldin A1 A M Adesina A1 D L Cass A1 M Hirano A1 J R Lupski A1 F Scaglia YR 2004 UL http://jmg.bmj.com/content/41/2/125.abstract AB Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive multisystem disorder caused by thymidine phosphorylase (TP) deficiency, resulting in severe gastrointestinal dysmotility and skeletal muscle abnormalities. A patient is reported with a classical MNGIE clinical presentation but without skeletal muscle involvement at morphological, enzymatic, or mitochondrial DNA level, though gastrointestinal myopathy was present. MNGIE was diagnosed by markedly raised plasma thymidine and reduced thymidine phosphorylase activity. Molecular genetic analysis showed a homozygous novel splice site mutation in TP. On immunohistochemical studies there was marked TP expression in the CNS, in contrast to what has been observed in rodents. It is important to examine the most significantly affected tissue and to measure TP activity and plasma thymidine in order to arrive at an accurate diagnosis in this condition.