Ocular involvement in Niemann-Pick disease type B

Morbidity and mortality in type B Niemann-Pick disease

PURPOSE

The purpose of this study was to perform a systematic evaluation of morbidity and mortality in type B Niemann-Pick disease.

METHODS

A total of 103 patients with Niemann-Pick disease (49 males, 54 females, age range: 1-72 years) participated in natural history studies through Mount Sinai's International Center for Types A and B Niemann-Pick Disease between 1992 and 2012.

RESULTS

Serious morbidities included significant neurological, hepatic, and cardiac disease. Thirteen patients had some degree of neurological impairment. Nine patients had cirrhosis or liver failure requiring transplantation. Coronary artery and valvular heart disease were present in nine patients. Of note, only four patients were oxygen dependent, although progressive pulmonary disease is a well-described feature of Niemann-Pick disease. During the follow-up period, 18 deaths occurred. The median age of death was 15.5 years (range 1-72). Causes of death included pneumonia, liver failure, and hemorrhage. The majority of deaths (12 of 18) occurred in patients <21 years, yielding a mortality rate of 19% in the pediatric population.

CONCLUSION

This study demonstrates that Niemann-Pick disease is a life-threatening disorder with significant morbidity and mortality, especially in the pediatric population. The information collected in this series highlights the need for safe, effective therapy for Niemann-Pick disease.

Early pulmonary involvement in Niemann-Pick type B disease: lung lavage is not useful

Niemann-Pick disease (NPD) is a rare, autosomal-recessively inherited lipid storage disease which is characterized by intracellular deposition of sphingomyelin in various body tissues. The disease is heterogeneous and classified into six groups. Pulmonary parenchymal involvement may be a feature of several subtypes of NPD, including type B. Progressive pulmonary involvement in NPD type B is a major cause of morbidity and mortality. It is usually diagnosed at older ages. Only a few cases with early pulmonary involvement have been reported. In this report, a patient with NPD type B, hospitalized with the diagnosis of pneumonia at age 3 months, is presented. Following treatment for pneumonia, she continued to have persistent respiratory symptoms and became oxygen-dependent. High-resolution computed tomography of the chest revealed diffuse interstitial changes. During follow-up, the patient developed hepatosplenomegaly. Lung, liver, and bone marrow biopsies showed characteristic findings for NPD. Biochemical studies also confirmed the diagnosis, and the sphingomyelinase enzyme level of the patient was low. Unilateral lung lavage was performed in order to decrease lipid storage as a treatment modality. However, there was no clinical or radiological improvement. The patient died at age 15 months due to progressive respiratory failure. Pulmonary involvement is a rare entity in early childhood in patients with NPD type B, but should be considered in the differential diagnosis of persistent interstitial lung disease. It may cause progressive respiratory failure, but the treatment options remain limited.

The natural history of type B Niemann-Pick disease: results from a 10-year longitudinal study

OBJECTIVES

Type B Niemann-Pick disease (NPD-B) caused by acid sphingomyelinase deficiency is a rare, autosomal recessive, lysosomal storage disorder with a broad range of disease severity. The objectives of this study were to document the natural history of the disease in a large, clinically heterogeneous patient population that was followed for a period of 10 years and to determine how genotype influences phenotype.

METHODS

Twenty-nine patients with NPD-B had serial evaluations at least 9 months apart. Organ volumes, hematologic indices, lipid concentrations, pulmonary function, and hepatic activity were studied, and individual phenotypic severity was compared with genotype.

RESULTS

All patients with intact spleens had splenomegaly (mean value: 12.7 multiples of normal [MN]; range: 4.5-27.3 MN), and all but 1 had hepatomegaly (mean volume: 1.91 MN; range: 0.93-3.21 MN). At initial visit, 39% had thrombocytopenia and 3% had leukopenia. At final visit, the percentages increased to 54% and 34%, respectively. Mean annual decreases in platelet count and leukocyte count were 7 x 10(3) and 0.2 x 10(3) per mm3, respectively. The typical atherogenic lipid profile was worse in older patients. A total of 69% of patients had low diffusion capacity for carbon monoxide, and more than one third had low forced expiratory volume in 1 second, forced vital capacity, and forced expiratory volume in 1 second/forced vital capacity at initial visit. All measurements of pulmonary function showed a gradual deterioration over time. Liver dysfunction was characterized by stable elevation of hepatic transaminases and bilirubin. Homozygotes for DeltaR608, P323A, and P330R had milder disease than patients with all other genotypes.

CONCLUSIONS

The natural history of NPD-B is characterized by hepatosplenomegaly with progressive hypersplenism, worsening atherogenic lipid profile, gradual deterioration in pulmonary function, and stable liver dysfunction.

Ocular manifestations of Niemann–Pick disease type B

PURPOSE

To investigate the ocular manifestations in Niemann-Pick disease type B (NPD-B).

DESIGN

Observational case series.

PARTICIPANTS

Forty-five patients (23 male and 22 female) with NPD-B from 37 unrelated families.

METHODS

Serial clinical evaluations were carried out over a 2- to 14-year period, including a complete physical examination, neurologic assessment, and ophthalmologic examination. Genotyping of the specific mutations in the acid sphingomyelinase (ASM) gene was performed when possible for genotype-phenotype correlations.

MAIN OUTCOME MEASURES

Fundus photographs to evaluate the retina, ASM genotype, and neurologic examination findings.

RESULTS

Ophthalmoscopic examination revealed retinal stigmata in 15 of 45 patients, 3 with macular halos and 12 with cherry red maculae. Neurologic examinations did not reveal any evidence of neurodegeneration, and there was no consistent relationship between retinal findings and genotype.

CONCLUSIONS

The presence of macular halos and/or cherry red maculae is not an absolute predictor of neurodegeneration, but should prompt a thorough evaluation to determine the underlying etiology and the precise diagnosis.

Growth restriction in children with type B Niemann-Pick disease

OBJECTIVES

To compare growth of children with type B Niemann-Pick disease (NPD) with disease variables including genotype, organomegaly, bone age, and serum insulin-like growth factor-1 (IGF-1).

STUDY DESIGN

A cross-sectional analysis of growth was performed in 23 children and adolescents with enzymatically and genotypically confirmed NPD. Liver and spleen volumes were measured by quantitative computed tomography and skeletal age by a wrist radiograph.

RESULTS

The mean Z scores for height and weight were -1.24 (29th percentile) and -0.75 (34th percentile). The mean liver and spleen volumes were 2.06 and 13.46 times normal for weight, respectively. Skeletal age was delayed by an average of 2.5 years, and serum IGF-1 level was at or below the 2nd percentile in 8 of 12 patients. Short stature and low weight were significantly correlated with large organ volumes, delayed bone age, and low IGF-1 levels. In contrast to patients with other mutations, individuals homozygous for the DeltaR608 mutation had normal height and weight, markedly less hepatosplenomegaly and bone age delay, and normal IGF-1 levels.

CONCLUSIONS

Abnormal linear growth and delayed skeletal maturation are common in children and adolescents with type B NPD; however, homozygosity for DeltaR608 is associated with normal growth.

Pulmonary involvement in Niemann-Pick disease: case report and literature review

Niemann-Pick disease (NPD) is a rare, inherited, autosomal recessive, lipid storage disease. The pathognomonic intracellular accumulation of sphingomyelin results in the production and accumulation of 'foam cells'. Interstitial lung disease is a rare manifestation of NPD. We present the case of a 48-year-old white female with NPD involving the lungs, liver and spleen. The chest radiograph showed bilateral, predominantly basal reticulonodular infiltrates and serial pulmonary function tests over a period of years showed preserved expiratory airflow and a severely decreased diffusion capacity for carbon monoxide (DLCO). In view of her visceral involvement, lack of neurological symptoms and survival into adulthood, we believe our patient represents a case of type B NPD. In this type of NPD, aside from prominent hepatosplenomegaly and sexual immaturity, significant pulmonary infiltration with 'Pick cells' has been reported. To date, no therapeutic modality has been shown to alter the natural history of this disease, which results in progressive debilitation and death. This case is unique in that it provides the longest physiological follow-up in the literature, and provides data on the natural history of pulmonary involvement in NPD.

A family with visceral course of Niemann-Pick disease, macular halo syndrome and low sphingomyelin degradation rate

We report a family with six patients suffering from a sphingomyelinase-deficient form of Niemann-Pick disease, all presenting with a visceral course of the disease. Retinal changes classified as macular halos in four members indicated neuronal storage and therefore an intermediate type of the disease. For further classification of the biochemical type, [choline-methyl-14C]sphingomyelin degradation studies were carried out in fibroblast cultures of all six members. The low degradation rates measured were similar to those usually found in the neuronopathic form (type A) of Niemann-Pick disease. This family illustrates the broad heterogeneity within the sphingomyelinase deficiency group of the Niemann-Pick disease. Apparently the finding of a low sphingomyelin degradation rate in fibroblast cultures does not necessarily imply a typical serious and lethal course of the disease.

Niemann-Pick disease

Results of the investigation carried out during this decade brought unambigous evidence of biochemical heterogeneity inside the complex of Niemann-Pick disease according to which two entirely different metabolic disorders can be recognized. 1. Niemann-Pick sphingomyelinosis, a clear-cut enzymopathy, the pivotal lesion of which is the deficiency of lysosomal spingomyelinase leading to widespread lysosomal deposition of sphingomyelin liquid crystals. Two main allelic variants are known. The first one, neuronopathic (former type A) known as infantile with rapid course, may also manifest considerably prolonged course or an atypical course with predominantly visceral symptomatology. Patients with the second, visceral, variant (former type B), display mainly slow clinical course and often reach adulthood. With rare exceptions the neuronopathic variant can be biochemically recognized from the visceral one by much lower values of the in vivo sphingomyelin degradation test in the former. 2. The rest of the complex comprising types C-D differs substantially from the sphingomyelinase deficiency group by the remarkable heterogeneity in the lysosomal stored lipid pattern given by differences among the affected cell populations. Sphingomyelin storage could be proved histochemically solely in the histiocytic population together with cholesterol, neutral glycosphingolipids and lysobisphosphatidic acid, whereas the brain neurons displayed only neutral glycosphingolipid storage. There is an increasing evidence of the crucial biochemical lesion in this group being an altered intracellular traffic of exogenously derived cholesterol caused probably by its deficient translocation from lysosomes to other intracellular membrane sites. This leads to decreased cholesterol esterification rate which is the basis of the newly developed diagnostic test. Inconstant depression of sphingomyelinase activity is considered to be a secondary phenomenon. The so-called lactosylceramidosis is a rare variant pertinent to this group. The biochemical nature of type E still awaits clarification. Both groups of Niemann-Pick disease display clinical and especially histochemical features which allows to establish diagnosis in a highly efficient way already at the clinicopathological level.