Lysosomal storage disease as an etiology of nonimmune hydrops

We performed a systematic review of the literature to evaluate the incidence and types of lysosomal storage disorders (LSDs) in case series of nonimmune hydrops (NIH). PubMed and Ovid were reviewed for case series evaluating the workup of NIH diagnosed in utero or in the neonatal period in human subjects. Search terms were as follows: nonimmune hydrops, non immune hydrops, metabolic genetic disorders, and lysosomal storage disorders. The time period searched was 1979 through January 2014. Retrospective case series with at least 5 cases of fetal and/or neonatal NIH with its workup mentioned were identified. Idiopathic NIH was defined as NIH without an apparent cause after an initial workup. Exclusion criteria included studies published in languages other than English and review articles. The 3 authors screened all abstracts and manuscripts independently. Metaanalysis of Observational Studies in Epidemiology guidelines were followed. Fifty-four case series with 678 total cases of NIH were identified. The overall incidence of LSD was 5.2% (35 of 678) in all NIH cases that tested for any LSD and 17.4% (35 of 201) in idiopathic NIH cases. The 3 most common LSDs identified in cases of NIH, in order of decreasing incidence, were Mucopolysaccharidosis type VII, Gaucher's disease, and GM1-gangliosidosis. LSDs occur in 5.2% of all NIH cases and in 17.4% of idiopathic NIH cases and so should be screened for in this clinical scenario. Additionally, if a comprehensive LSD workup is completed on idiopathic cases, 29.6% of those would be reclassified as LSD. LSD testing does not only allow diagnosis but also ensures better counseling, appropriate management, and planning for possible early intervention. Moreover, their detection may aid in a prenatal diagnosis in subsequent pregnancies.