The clinical presentation of lysosomal storage disorders.

Lysosomal storage disorders (LSDs) are present from conception and produce a clinical phenotype that evolves with time. The introduction of new therapies has made early diagnosis a priority. Clues to the clinical diagnosis of a LSD can be found in the tempo of the illness especially if the central nervous system is involved. Loss of a previously acquired skill (regression) is very characteristic of this group of disorders. Other clinical clues can include a dysmorphic appearance or the presence of characteristic skeletal involvement (dysostosis multiplex), but in some disorders such as Pompe disease or Krabbe disease, these do not occur. The approach to diagnosis has to involve "screening" as there can be considerable overlap in clinical presentation (e.g. Gaucher disease and Niemann-Pick B). Both urine and blood testing are necessary and the majority of diagnoses can now be confirmed at a molecular level. Prenatal diagnosis is possible for all.