Metabolic Services, Genetic Health Services Victoria, Royal Children's Hospital, Melbourne, Australia.
J Inherit Metab Dis. 2008 Dec;31 Suppl 2:S281-5. doi: 10.1007/s10545-008-0859-0. Epub 2008 Nov 10.
Maple syrup urine disease (MSUD) is a very rare disorder of branched-chain amino acid metabolism. However, it is the most common inborn error of metabolism in the Philippines. We present a retrospective review of 21 patients diagnosed with MSUD between 1999 and 2004. The patients presented clinically between 2 and 14 days of life (mean 5 days) and the diagnosis of MSUD was established between 6 days and 11 months of age (mean 39 days). The classical burnt sugar odour was noted in the majority of patients (81%). The diagnosis of MSUD was initially based on clinical suspicion and confirmed biochemically by measurement of leucine/isoleucine levels by thin-layer chromatography. The acute management included removal of accumulated branched-chain amino acids by peritoneal dialysis in 62% of the patients. Mortality rate of this group of patients was 24% and follow-up rate was 87%. We compared this series with a previously reported series of 26 patients to determine whether diagnosis and the management of MSUD improved over the two periods. Four cases have been diagnosed early since 1992, the majority of whom had the classic form of MSUD with the onset of symptoms in the first two weeks of life. A small subset of patients with early nonspecific symptoms was diagnosed much later owing to a low-level clinical suspicion among clinicians. Overall, however, there appears to be a small but general trend towards earlier diagnosis, reduced mortality and long-term follow up in the later series. Although we are able to diagnose and manage MSUD in the Philippines, we recognize that the clinical outcome remains poor and is due mainly to late referral of cases and inadequate long-term management. In the Philippines, we recommend that all newborns who are considered to be septic, have feeding difficulties, fail to regain their birth weight or present with any other symptoms suggestive of MSUD be evaluated in the first instance by analysis of urine for ketones and if they are positive have blood collected and sent to our laboratory for leucine/isoleucine measurement.
枫糖尿症（MSUD）是一种非常罕见的支链氨基酸代谢紊乱疾病。然而，它是菲律宾最常见的先天性代谢错误。我们回顾性分析了 1999 年至 2004 年间诊断为 MSUD 的 21 例患者。患者的临床表现为出生后 2 至 14 天（平均 5 天），MSUD 的诊断发生在 6 至 11 个月龄（平均 39 天）。大多数患者有典型的焦糖气味（81%）。MSUD 的诊断最初基于临床怀疑，并通过薄层层析测量亮氨酸/异亮氨酸水平来确认。62%的患者采用腹膜透析清除积聚的支链氨基酸进行急性治疗。该组患者的死亡率为 24%，随访率为 87%。我们将本系列与之前报道的 26 例患者进行比较，以确定在这两个时期 MSUD 的诊断和治疗是否有所改善。自 1992 年以来，有 4 例患者被早期诊断，其中大多数为有症状的经典 MSUD，发病时间在出生后两周内。由于临床医生的临床怀疑水平较低，一小部分具有早期非特异性症状的患者被诊断为较晚。然而，总体而言，后来的系列似乎有一个较小但普遍的趋势，即更早的诊断，降低死亡率和长期随访。尽管我们能够在菲律宾诊断和治疗 MSUD，但我们认识到临床结果仍然不佳，主要是由于病例的晚期转诊和长期管理不足。在菲律宾，我们建议所有被认为是败血症、有喂养困难、未能恢复出生体重或有任何其他提示 MSUD 症状的新生儿，首先通过分析尿液中的酮体进行评估，如果呈阳性，应采集血液并送到我们的实验室进行亮氨酸/异亮氨酸测量。
