Cystathionine beta-synthase (CBS) deficiency is a rare inherited disorder in the methionine catabolic pathway, in which the impaired synthesis of cystathionine leads to accumulation of homocysteine. Patients can present to many different specialists and diagnosis is often delayed. Severely affected patients usually present in childhood with ectopia lentis, learning difficulties and skeletal abnormalities. These patients generally require treatment with a low-methionine diet and/or betaine. In contrast, mildly affected patients are likely to present as adults with thromboembolism and to respond to treatment with pyridoxine. In this article, we present recommendations for the diagnosis and management of CBS deficiency, based on a systematic review of the literature. Unfortunately, the quality of the evidence is poor, as it often is for rare diseases. We strongly recommend measuring the plasma total homocysteine concentrations in any patient whose clinical features suggest the diagnosis. Our recommendations may help to standardise testing for pyridoxine responsiveness. Current evidence suggests that patients are unlikely to develop complications if the plasma total homocysteine concentration is maintained below 120 μmol/L. Nevertheless, we recommend keeping the concentration below 100 μmol/L because levels fluctuate and the complications associated with high levels are so serious.

Patients with EH have an altered profile of pro-and anti-inflammatory cytokines, consistent with monocyte activation in the circulation. The importance of these changes for the pathogenesis of EH and/or its secondary complications remains to be elucidated.

Questionnaires are widely used instruments to monitor gastrointestinal (GI) symptoms. However, few of these questionnaires have been formally evaluated. We sought to evaluate our GI symptoms questionnaire in terms of clarity and reproducibility. Primary care patients referred for open access Helicobacter pylori urea breath testing reported GI symptoms (type+severity) and demographic information by written questionnaire. In an interview, patients gave a personal description of the meaning of the GI symptoms on the questionnaire. Patients' descriptions of GI symptoms were compared with current definitions. Symptom severity scores were compared before and after, interview versus questionnaire. Of the 45 patients included, 19 (42%) described all symptoms correctly, whereas 17 (38%) described one symptom incorrectly. None of the patients made more than three mistakes. Regurgitation was the most common incorrectly described symptom (16 patients [36%]), whereas the other individual symptoms were well explained. Symptom severities before the interview, after the interview and reported by questionnaire (mean value+/-SEM) were 2.1 +/- 0.2, 2.1 +/- 0.2, and 1.5 +/- 0.2 points on a 7-point Likert scale (0-6), respectively. Mean severity reported by interview (95% CI) was 1.4 (1.3-1.5) times higher than reported by questionnaire (P < .05). In conclusion, the GI symptom questionnaire is understandable and has good reproducibility for measuring the presence of GI symptoms, although symptom severity is consistently rated higher when reported by interview.

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A wide spectrum of IEM are followed at adult centres. Specific knowledge of these disorders is needed to provide optimal care including up-to-date knowledge of treatments and ability to manage acute decompensation.