Niemann-Pick disease type B: an unusual clinical presentation with multiple vertebral fractures

Abstract

We report here a unique case of a 55-year-old woman presenting with a clinical picture of Parkinson disease, severe back pain, splenomegaly, and pronounced dyspnea. Radiographic examination of the spine showed multiple vertebral fractures. Niemann-Pick disease type B was diagnosed by findings of lipid-loaded histiocytes and a strongly reduced sphingomyelinase enzyme activity. She was homozygous for the deletion of codon 608 (delR608), which encodes an arginine residue in the Acid Sphingomyelinase gene. To investigate the cause of the unusual vertebral fractures, we screened for polymorphisms previously described as possibly associated with increased risk for osteoporosis and fractures. Our patient was heterozygous for the polymorphisms of the vitamin D receptor gene, the estrogen receptor gene, and the collagen 1A1gene. Increased physical activity after Parkinson treatment, a genetic predisposition, together with worsening disease due to interfering medications could explain the dramatic presentation of this patient. She was treated with cholesterol lowering drugs such as statins to decrease sphingomyelin synthesis, avoidance of drugs that inhibit sphingomyelinase, and bisphosphonates. No new fractures have occurred, but the interstitial lung disease has progressed.