Lysosomal disorders.

Although most lysosomal storage disorders present in infancy or early childhood with a progressive condition often associated with dysmorphism, considerable genetic heterogeneity exists resulting in a range of illnesses that can include a dramatic neonatal presentation. Whilst some conditions present with a characteristic neonatal phenotype (e.g. Niemann-Pick disease type C), the remainder present in a nonspecific way often with non-immune hydrops fetalis. Diagnosis can be helped by appropriate radiological studies and, in some patients, evidence of the storage phenomena can be seen in peripheral blood smears or bone marrow aspirates. Unfortunately, for the majority of affected patients no effective, curative, treatment is possible. New developments in therapy including enzyme replacement therapy and substrate deprivation may improve prognosis in some disorders. It is important to establish an accurate diagnosis, as prenatal testing can then be offered in future pregnancies.