Niemann-Pick disease type-B: a unique case report with compound heterozygosity and complicated lipid management

Background

Niemann-Pick disease (NPD) is a rare autosomal recessive hereditary disease characterized by deficient activity of acid sphingomyelinase.

Case presentation

We present a case of NPD type B with a unique compound heterozygosity for SMPD1 (NM_000543.4:c.[84delC];[96G > A]) in which both mutations that induce an early stop codon are located before the second in-frame initiation codon. The clinical presentation of the patient is compatible with NPD type B. She was initially diagnosed of Gaucher Disease, but her altered lipid profile led to a clinical suspicion of NPD.

Combined high doses of atorvastatin and ezetimibe were given to treat the severe hypercholesterolemia.

Conclusions

The pharmacological management of the lipid profile in these patients is important. A unique compound mutation in SMPD1 gene is described.

Agreement between results of meta-analyses from case reports and clinical studies, regarding efficacy and safety of idursulfase therapy in patients with mucopolysaccharidosis type II (MPS-II). A new tool for evidence-based medicine in rare diseases

Background

A preliminary exploratory study shows solid agreement between the results of case reports and clinical study meta-analyses in mucopolysaccharidosis Type I (MPS-I) adult patients. The aim of the present study is to confirm previous results in another patient population, suffering from mucopolysaccharidosis Type II (MPS-II).

Methods

A systematic review and meta-analysis of case reports published by April 2018 was conducted for MPS-II patients treated with enzyme replacement therapy (ERT). The study is reported in accordance with PRISMA and MOOSE guidelines (PROSPERO database code CRD42018093408). The assessed population and outcomes were the same as previously analyzed in a meta-analysis of MPS-II clinical studies. The primary endpoint was the percent of clinical cases showing improvement in efficacy outcome, or no harm in safety outcome after ERT initiation. A restrictive procedure to aggregate case reports, by selecting standardized and well-defined outcomes, was proposed. Different sensitivity analyses were able to evaluate the robustness of results.

Results

Every outcome classified as “acceptable evidence group” in our case report meta-analysis had been graded as “moderate strength of evidence” in the aforementioned meta-analysis of clinical studies. Sensitivity, specificity, and positive-negative predictive values for results of both meta-analyses reached 100%, and were deemed equivalent.

Conclusions

Aggregating case reports quantitatively, rather than analyzing them qualitatively, may improve conclusions in rare diseases and personalized medicine. Additionally, we propose some methods to evaluate publication bias and heterogeneity of the included studies in a meta-analysis of case reports.

Efficacy of Idursulfase therapy in patients with Mucopolysaccharidosis type II who initiated enzyme replacement therapy in adult age. A systematic review of the literature

BACKGROUND

Enzyme replacement therapy (ERT) has been shown to decrease urine glycosaminoglycans (uGAGs) and liver and spleen volumes, and to improve clinical symptoms in mucopolysaccharidosis type II (MPS-II) patients.

METHODS

A systematic search of the literature, from inception to August 2017, was conducted to identify randomized trials or observational studies including ≥1 MPS-II patients with ERT initiated in adult age (≥16 years) and evaluating ERT efficacy. Evidence was rated according to GRADE criteria. Common efficacy outcomes of the clinical studies were analyzed. Case reports were separately evaluated.

RESULTS

One randomized clinical trial, 4 observational studies and 5 case reports were selected. ERT decreased uGAG levels and liver and spleen size with moderate evidence level and led to anti-ERT antibody and IRRS development in a significant proportion of patients with moderate evidence level. There were no conclusive results for beneficial effects on 6MWT, respiratory, cardiac and neurological function, joint mobility, sleep disorders of respiratory origin, and quality of life.

LIMITATIONS

Excluding one observational study, all others were not conducted specifically in the target population (ERT ≥16 years). Data were from subgroup analyses of selected studies. There was a great heterogeneity between study designs and clinical outcomes evaluated.

CONCLUSIONS

ERT improves uGAGs and liver/spleen volume with a moderate evidence level in MPS-II patients initiating therapy as adults, although the putative associated clinical benefit is unclear.

Agreement between the results of meta-analyses from case reports and from clinical studies regarding the efficacy of laronidase therapy in patients with mucopolysaccharidosis type I who initiated enzyme replacement therapy in adult age: An example of case reports meta-analyses as an useful tool for evidence-based medicine in rare diseases

BACKGROUND

Case reports might have a prominent role in the rare diseases field, due to the small number of patients affected by one such disease. A previous systematic review regarding the efficacy of laronidase therapy in patients with mucopolysaccharidosis type I (MPS-I) who initiated enzyme replacement therapy (ERT) in adult age has been published. The review included a meta-analysis of 19 clinical studies and the description of eleven case reports. It was of interest to perform a meta-analysis of those case reports to explore the role of such meta-analyses as a tool for evidence-based medicine in rare diseases.

METHODS

The study included all case reports with standard treatment regimen. Primary analysis was the percentage of case reports showing an improvement in a specific outcome. Only when that percentage was statistically higher than 5%, the improvement was confirmed as such. The outcomes that accomplished this criterion were ranked and compared to the GRADE criteria obtained by those same outcomes in the previous meta-analysis of clinical studies.

RESULTS

There were three outcomes that had a significant improvement: Urine glycosaminoglycans, liver volume and 6-minute walking test. Positive and negative predictive values, sensitivity and specificity for the results of the meta-analysis of case reports as compared to that of clinical studies were 100%, 88.9%, 75% and 100%, respectively. Accordingly, absolute (Rho=0.82, 95%CI: 0.47 to 0.95) and relative agreement (Kappa=0.79, 95%CI: 0.593 to 0.99) between the number of case reports with improvement in a specific outcome and the GRADE evidence score for that outcome were good. Sensitivity analysis showed that agreement between the meta-analysis of case reports and that of the clinical studies were good only when using a strong confirmatory strategy for outcome improvement in case reports.

CONCLUSIONS

We found an agreement between the results of meta-analyses from case reports and from clinical studies in the efficacy of laronidase therapy in patients with MPS-I who initiated ERT in adult age. This agreement suggests that combining case reports quantitatively, rather than analyzing them separately or qualitatively, may improve conclusions in the field of rare diseases.