How do symptoms vary in patients with Niemann-Pick type C disease?
Recognition of symptoms, by both families and healthcare professionals, is an important part of diagnosing Niemann-Pick type C disease (NP-C). Recent research involving in-depth interviews with parents or carers of patients with NP-C confirmed that symptoms are variable, not specific to the disease and appear or are recognized at different times.1 The average time from onset of noticeable symptoms to diagnosis amongst the 26 families interviewed was slightly over five years. By discussing the journey to diagnosis for each family, three specific patient types were identified according to the symptoms and the time taken to diagnosis; those with visceral symptoms, those with learning difficulties and those with psychiatric symptoms (see Table 1).1 Knowing more about the type of symptoms and when they might occur may help you access the correct specialist medical help.
Table 1: Three typical NP-C patient journeys to diagnosis1,2
|Visceral symptoms||Learning difficulties||Psychiatric symptoms|
|Typical symptoms experienced||Child is born with visceral symptoms, such as an enlarged liver or spleen and/or suffering from jaundice||Child starts to have difficulties with coordination, frequent falls and can struggle at school||Psychiatric symptoms, such as hallucinations, aggressive behavior or paranoia, may develop in the teenage years|
|Typical diagnosis journey||Usually diagnosed quickly after birth, particularly if the symptoms are severe||Often misdiagnosed as having dyslexia (problems with reading) or dyspraxia (problems with planning or coordinating movement)||Often misdiagnosed with schizophrenia, autism or bipolar disorder|
|Possible reason for delay in diagnosis||The visceral symptoms are not specific to NP-C, may not be recognized or followed up as they subside by themselves over time so the initial opportunity to diagnose NP-C may be missed. It can often be years before other symptoms develop||The family may see a series of specialists (such as neurologists, metabolic specialists, liver specialists or psychiatrists) over a period of years before NP-C is identified||Physical symptoms are often not detected, or thought to be side effects of medication, which means that they can remain in psychiatric care until these symptoms appear more prominently and are recognized by a healthcare professional|
Visceral symptoms, such as an enlarged liver or spleen are often the first symptoms patients with NP-C present with. These may be present alongside jaundice at birth. When recognized, the family is generally referred immediately to a liver specialist to rule out other possible illnesses. A diagnosis of NP-C is then confirmed using biochemical and genetic tests (see Diagnosing NP-C).1
Not all symptoms are recognized in infancy. A physical problem may go unnoticed until a child experiences learning difficulties at school. This may not happen until they are aged between four and eight years, but sometimes it can be later. These symptoms are similar to dyslexia (problems with reading) or dyspraxia (problems with planning or coordinating movement). The gradual decline can be confused with general school difficulties and can be difficult to see at home. A parent or teacher may notice memory and learning difficulties, lack of coordination, exhaustion or frequent falls but the problem is usually only flagged when children fall far behind their peers or they start to lose their acquired skills. Diagnosis of NP-C via this route has been known to take up to nine years.1
Not all learning difficulties are recognized or viewed as severe enough to be linked to the possibility of NP-C. In these patients, psychiatric symptoms such as psychosis (for example hallucinations or delusions) emerge in the teenage years before other, physical symptoms are noticed and are commonly misdiagnosed as schizophrenia, autism with psychotic features or bipolar disorder. When a patient also presents with balance problems and slurred speech, these are often mistakenly attributed to side effects of medication. These patients often experience the longest journey to diagnosis, some involving up to 19 years of generalist and specialist psychological or psychiatric care, before a diagnosis of NP-C is confirmed.1
- Niemann-Pick type C disease: Journey to Diagnosis. A Patient Report. September 2010.
- Patterson MC, Hendriksz CJ, Walterfang M, et al, on behalf of the NP-C Guidelines Working Group. Recommendations for the diagnosis and management of Niemann–Pick disease type C: An update. Mol Genet Metab 2012. 106(3):330-344.