The association between type 1 Gaucher disease and PD has been reported in the literature. The clinical picture is characterized by the predominance of bilateral akinetic-rigid signs and poor response to levodopa therapy. The authors describe four patients (two siblings) with type 1 Gaucher disease presenting with the following signs of typical PD: asymmetric onset of rigidity, resting tremor, bradykinesia, and a favorable response to Parkinson therapies.

For paediatric patients with Gaucher disease, enzyme replacement therapy (ERT) has the potential to prevent the development of serious, irreversible skeletal complications. Analysis of skeletal data for paediatric patients receiving ERT must take into account the pubertal growth spurt and developmental changes in bone marrow composition. In a study conducted at the Burlo Garofolo Institute in Trieste, Italy, 10 paediatric patients have received ERT, and data are available for 3-9 years of follow-up. ERT was associated with a significant increase in the mean lumbar bone mineral density (BMD) Z score after 2 years of treatment (p=0.003). Skeletal growth rates increased among patients exhibiting growth delays. At the Gaucher Disease Treatment Center in Cincinnati, OH, USA, a total of 11 paediatric patients have been followed for 2 years or more of ERT. Of these 11 patients, 6 have demonstrated significant increases in lumbar BMD after 2 years of ERT; these patients tended to have lower BMD Z scores at the start of ERT. At the Children's Hospital of the Johannes-Gutenberg University in Mainz, Germany, 7 children with type 1 Gaucher disease presented with reduced BMD in the distal ulna, and after 18-24 months of ERT, these patients demonstrated increases in BMD at this site. The patients exhibiting growth retardation experienced growth acceleration during treatment. These studies suggest that ERT improves BMD and growth rates in paediatric patients with Gaucher disease. ERT in paediatric patients may have the potential to prevent serious skeletal complications such as fractures and vertebral compression later in life.

Glycogenosis type 2 is an autosomal recessive glycogen storage disorder caused by deficiency of lysosomal acid alpha-glucosidase. Different phenotypes are recognized. The authors describe two children affected by the late infantile form; both presented terminal hyperthermia not caused by infections. Autopsy performed in one case showed diffuse glycogen storage in the CNS neurons. In light of current interest in enzyme replacement therapy, this finding casts some doubt on how effective enzyme replacement therapy will be unless it can be targeted directly into the CNS.

Bone involvement is one of the most disabling aspects of type I Gaucher disease and its pathophysiology is still not well understood. As an invasive procedure, bone biopsies are not appropriate in a large population study. The development of sensitive bone resorption and formation tests have allowed the authors to study bone metabolism in a noninvasive manner in a group of type 1 Gaucher patients. Ten type I Gaucher adult patients with mild-to-severe bone disease were evaluated. Bone mineral density and markers of bone formation (total alkaline phosphatase and isoenzymes, carboxyterminal propeptide of type I procollagen, osteocalcin) and resorption (carboxyterminal telopeptide of type I collagen, urinary hydroxyproline, free-deoxypyridinoline and calcium) were measured in patients and in a control group, matched for sex and age. In Gaucher patients, carboxyterminal propeptide of type I procollagen (PICP), a bone formation index, was significantly lower compared with normal subjects (mean 101.17 ng/ml vs 140.75 ng/ml, P = 0.038), and analysis of bone resorption indexes showed a significant increase (mean 4.24 ng/ml vs 2.87 ng/ml, P = 0.012) of serum carboxyterminal telopeptide of type I collagen (ICTP). No significant differences were observed in osteocalcin, alkaline phosphatase, and urinary hydroxyproline. Bone mineral density revealed osteopenia in six patients, with a mean Z-score of ?1.04. It was not possible to show a relationship between sex, splenectomy status, age, weight, spleen, and liver volume and bone density, expressed as a Z-score nor a correlation between Z score and severity of skeletal disease. Results have shown a predominance of the resorption phase in the bone metabolism of Gaucher patients. These markers could be useful in monitoring the effect of enzyme replacement therapy on Gaucher disease skeletal involvement.