Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare neurodegenerative multisystem disorder inherited in an autosomal recessive manner and characterized clinically by gastrointestinal dysmotility, cachexia, ophthalmoparesis and/or ptosis, peripheral neuropathy and leukoencephalopathy. Heterogenous causative mutations in the thymidine phosphorylase (TP) gene located on chromosome 22q13 have been identifi ed. This is the fi rst reported case of a 25-year-old Malaysian patient, of indigenous Bajau ethnicity who presented with recurrent abdominal pain before developing other clinical features of classical MNGIE. Biochemical correlates include elevated plasma levels of thymidine, deoxyuridine and lactate. The brain MRI showed diffuse leucoencephalopathy while nerve conduction studies were consistent with demyelinating polyneuropathy. Direct DNA sequencing of the nine coding exons of the TP gene showed both a novel and a previously described mutation. The former is a point mutation in exon 5 (NG_011860.1:g.7387C>T) at amino acid position 179, resulting in a stop codon and premature truncation of thymidine phosphorylase(TP) protein while the latter mutation occurred at exon 10 (NG_011860.1:g.9279C>T) resulting in a missense homozygous mutation at amino acid position 471. Defi nite diagnosis was based on clinical features, plasma and urinary nucleosides and the identifi cation of mutations in the TP gene. This case report adds to the knowledge of genotype-phenotype relationship of TP mutations and its occurrence among ethnic groups worldwide.

INTRODUCTIONA process-oriented instrument was developed for the summative assessment of student performance during problem-based learning (PBL) tutorials. This study evaluated (1) the acceptability of the instrument by tutors and (2) the consistency of assessment scores by different raters.

MATERIALS AND METHODSA survey of the tutors who had used the instrument was conducted to determine whether the assessment instrument or form was user-friendly. The 4 competencies assessed, using a 5-point rating scale, were (1) participation and communication skills, (2) cooperation or team-building skills, (3) comprehension or reasoning skills and (4) knowledge or information-gathering skills. Tutors were given a set of criteria guidelines for scoring the students' performance in these 4 competencies. Tutors were not attached to a particular PBL group, but took turns to facilitate different groups on different case or problem discussions. Assessment scores for one cohort of undergraduate medical students in their respective PBL groups in Year I (2003/2004) and Year II (2004/2005) were analysed. The consistency of scores was analysed using intraclass correlation.

RESULTSThe majority of the tutors surveyed expressed no difficulty in using the instrument and agreed that it helped them assess the students fairly. Analysis of the scores obtained for the above cohort indicated that the different raters were relatively consistent in their assessment of student performance, despite a small number consistently showing either "strict" or "indiscriminate" rating practice.

CONCLUSIONThe instrument designed for the assessment of student performance in the PBL tutorial classroom setting is user-friendly and is reliable when used judiciously with the criteria guidelines provided.

Education, Medical ; methods ; standards ; Educational Measurement ; methods ; Humans ; Problem-Based Learning ; standards ; Retrospective Studies ; Students, Medical ; Surveys and Questionnaires ; standards