A Suspicion Index to aid screening of early onset Niemann Pick disease Type C (NP C)
BackgroundNiemann Pick disease Type C (NP C) is difficult to diagnose due to heterogeneous and nonspecific clinical presentation. The NP C Suspicion Index (SI) was developed to identify patients with a high likelihood of NP C; however, it was less reliable in patients aged <4 years.MethodsAn early onset NP C SI was constructed following retrospective chart review of symptom presentation in 200 patients from nine centres comprised of 106 NP C cases, 31 non cases and 63 controls. Statistical analyses defined strength of association between symptoms and a diagnosis of NP C and assigned risk prediction scores to each symptom.ResultsVisceral symptoms were amongst the strongest predictors. Except for gelastic cataplexy and vertical supranuclear gaze palsy, central nervous system symptoms were not discriminatory in this population. Performance of the early onset NP C SI was superior versus the original NP C SI in patients aged =4 years.ConclusionsThe early onset NP C SI can help physicians, especially those with limited knowledge of NP C, to identify patients aged =4 years who warrant further investigation for NP C.
BMC Pediatrics