Phenotype diversity in type 1 Gaucher disease: discovering the genetic basis of Gaucher disease/hematologic malignancy phenotype by individual genome analysis.

Gaucher disease (GD), an inherited macrophage glycosphingolipidosis, manifests with an extraordinary variety of phenotypes that show imperfect correlation with mutations in the GBA gene. In addition to the classic manifestations, patients suffer from increased susceptibility to hematologic and nonhematologic malignancies. The mechanism(s) underlying malignancy in GD is not known, but is postulated to be secondary to macrophage dysfunction and immune dysregulation arising from lysosomal accumulation of glucocerebroside. However, there is weak correlation between GD/cancer phenotype and the systemic burden of glucocerebroside-laden macrophages. Therefore, we hypothesized that genetic modifier(s) may underlie the GD/cancer phenotype. In the present study, the genetic basis of GD/T-cell acute lymphoblastic lymphoma in 2 affected siblings was deciphered through genomic analysis. GBA gene sequencing revealed homozygosity for a novel mutation, D137N. Whole-exome capture and massively parallel sequencing combined with homozygosity mapping identified a homozygous novel mutation in the MSH6 gene that leads to constitutional mismatch repair deficiency syndrome and increased cancer risk. Enzyme studies demonstrated that the D137N mutation in GBA is a pathogenic mutation, and immunohistochemistry confirmed the absence of the MSH6 protein. Therefore, precise phenotype annotation followed by individual genome analysis has the potential to identify genetic modifiers of GD, facilitate personalized management, and provide novel insights into disease pathophysiology.

Pulmonary vascular disease in Gaucher disease: clinical spectrum, determinants of phenotype and long-term outcomes of therapy.

Pulmonary arterial hypertension (PAH) and hepatopulmonary syndrome (HPS) are rare pulmonary vascular complications of type 1 Gaucher disease (GD1). We examined GBA1 genotype, spleen status, Severity Score Index (SSI), and other patient characteristics as determinants of GD/PAH-HPS phenotype. We also examined the long-term outcomes of imiglucerase enzyme replacement therapy (ERT) +/- adjuvant therapies in 14 consecutive patients. We hypothesized a role of BMPR2 and ALK1 as genetic modifiers underlying GD/PAH-HPS phenotype. Median age at diagnosis of GD1 was 5 yrs (2-22); PAH was diagnosed at median 36 yrs (22-63). There was a preponderance of females (ratio 5:2). ERT was commenced at median 36.5 yrs (16-53) and adjuvant therapy at 36 yrs (24-57). GBA1 genotype was N370S homozygous in two patients, N370S heteroallelic in 12. Median SSI was 15 (7-20). All patients had undergone splenectomy at median age 12 yrs (2-30). In three patients, HPS was the initial presentation, and PAH developed after its resolution; in these three, HPS responded dramatically to ERT. In seven patients, sequencing of the coding regions of BMPR2 and ALK1 was undertaken: 3/7 were heterozygous for BMPR2 polymorphisms; none harbored ALK1 variants. With ERT (± adjuvant therapy), 5/14 improved dramatically, five remained stable, two worsened, and two died prematurely. In this largest series of GD/PAH-HPS patients, there is preponderance of females and N370S heteroallelic GBA1 genotype. Splenectomy appears essential to development of this phenotype. In some patients, HPS precedes PAH. BMPR2 and ALK1 appear not be modifier genes for this rare phenotype of GD. ERT +/- adjuvant therapy improves prognosis of this devastating GD phenotype.

Misdiagnosis of Niemann-Pick disease type C as Gaucher disease.

Niemann-Pick disease type C (NPC) is a model for inborn errors of metabolism whose gene product mediates molecular trafficking rather than catabolizing macromolecules, as in classic lipidoses. We report the case of an infant who presented with hepatosplenomegaly without neurological abnormalities. Decreased activity of acid ß-glucosidase and elevated serum chitotriosidase and tartrate-resistant acid phosphatase on repeated measurements led to initial diagnosis of Gaucher disease (GD). Failure to respond to enzyme replacement therapy after one year, however, put the diagnosis in question. Cholesterol esterification assays in cultured skin fibroblasts and NPC gene analysis led to the correct diagnosis of NPC. The patient had markedly reduced cholesterol esterification and was a compound heterozygote for a known and a novel mutation in the NPC gene (395delC and 2068insTCCC), which are both predicted to lead to protein truncation. Although the full phenotype of NPC involves hepatosplenomegaly and neurodegenerative disease, the initial presentation in a pediatric patient may be restricted to visceral disease. Of interest, this patient had decreased activity of leukocyte acid ß-glucosidase activity and elevated serum chitotriosidase to levels often seen in GD. Although acid ß-glucosidase activity in leukocytes was low, it was in the normal range in skin fibroblasts. Therefore, diagnostic delay may occur in NPC due to false positive testing for GD. Diagnosis of NPC requires a high index of suspicion and should be considered in a patient with hepatosplenomegaly even in the absence of neurodevelopmental signs. Prompt diagnosis will become increasingly important as effective therapies are developed for NPC.

Expanding spectrum of the association between Type 1 Gaucher disease and cancers: a series of patients with up to 3 sequential cancers of multiple types--correlation with genotype and phenotype.

In Gaucher disease (GD), inherited deficiency of lysosomal glucocerebrosidase due to mutations in GBA1 gene results in accumulation of glucosylceramide in tissue macrophages, systemic macrophage activation, and a complex multisystemic phenotype. We and others have reported an increased risk of multiple myeloma and other malignancies in non-neuronopathic Type 1 GD (GD1). Here, we describe a subset of GD1 patients with multiple malignancies. In our cohort of 403 patients with GD1, nine patients (2.2%) developed two or three different types of cancers either consecutively or simultaneously. Patients were characterized by age at diagnosis of GD1, GBA1 genotype, disease severity, age at cancer diagnosis, enzyme replacement therapy (ERT) status, and splenectomy status. Of the nine patients, six developed two types of malignancies and three had three cancers each. Overall, the hematologic malignancies comprised lymphoma/leukemia (4) and multiple myeloma (4). Nonhematologic malignancies included colon (2), lung (2), thyroid (2), and prostate cancer (1). Of the seven patients who received ERT, the first cancer was diagnosed before initiation of ERT in all but one. Asplenic patients were more likely to have single or multiple cancers compared with patients with intact spleens (P < 0.0072 and P < 0.0203, respectively). Our data strengthen the association of GD1 and cancer and suggest that patients may be at risk of developing multiple malignancies. We found an association between splenectomy and multiple cancers in GD1. It will be of interest to determine whether timely ERT and declining rates of splenectomy will translate into declining rates of multiple and single cancers.

Health literacy among English-speaking parents in a poor urban setting.

We surveyed English-speaking parents attending an inner-city health center. Subjects read the label on a bottle of liquid medicine and 1) demonstrated how much medicine they should give, 2) stated how many times a day they should give the medicine, and 3) stated when they should give the next dose. We calculated adjusted odds ratios to test for the likelihood of incorrect medication dosing for subjects with and without demographic risk factors. Three hundred twenty six subjects participated. Overall, 252 (77%) demonstrated incorrect medication dosing. Medication dosing was more likely to be incorrect among young parents (AOR 2.45; CI 1.14, 5.26), immigrants (AOR 2.27; CI 1.04, 4.96), subjects without a high school degree (AOR 2.05; CI 1.04,4.05), and those who did not recall ever having been shown how to use a medicine dropper (AOR 1.79; CI 1.01,3.19). Implications for practice are discussed.

Availability of Spanish prescription labels.

The research team conducted a cross-sectional telephone survey of all pharmacies in the Bronx, New York (99.4% participation rate) to determine availability of Spanish prescription labels. One hundred twenty five pharmacies (78%) were small independent pharmacies; 36 (22%) were large-chain pharmacies. Overall, 111 (69%) stated that they could provide prescription labels in Spanish. Overall, for all the pharmacy ZIP codes, the mean proportion of the population that was Spanish-speaking was 46.8% (range 11% to 71.6%). Seventy-eight (48%) pharmacies were located in areas where more than 50% of the population were Spanish-speaking, 48 (30%) were located in areas with 25.1-50% Spanish-speakers, and 35 (22%) were in areas with up to 25% Spanish-speakers. Small independent pharmacies were more likely than large chain pharmacies to provide prescription labels in Spanish (71% vs. 61%, p=0.25). All the pharmacists commented that a patient must specifically request a Spanish prescription label in order to receive one. Pharmacies located in areas with the highest proportion of Spanish speakers were more likely to provide prescription labels in Spanish (82% vs. 62% vs. 49%; p=.001). Of the 111 pharmacies that could provide Spanish labels, 95 (86%) used a computer program to perform the translation and 16(14%) used a lay employee. Of pharmacies using a computer program, only one had a Spanish-speaking pharmacist who could check and correct the computer translations.

Methotrexate levels and outcome in osteosarcoma.

BACKGROUND: Peak serum concentrations of methotrexate (MTX) have been reported to correlate with outcome in osteosarcoma (OS). Modification of the MTX dose to achieve peak levels between 700 and 1,000 micromol/L has been recommended. The goal of the study was to assess whether there is a correlation between histologic necrosis of the tumor and/or prognosis with peak MTX serum concentration. PROCEDURE: Treatment included multi-agent adjuvant chemotherapy, including high-dose MTX (12 g/m2). Peak MTX levels were drawn following a 4-hr infusion. Histologic evaluation for percent necrosis was done at the time of definitive resection. RESULTS: The median peak MTX level (n = 52 patients) was 1,060 micromol/L (range: 410-4,700 micromol/L), with significant intra-patient and inter-patient variability. Fifty-eight percent of the levels were 1,000 micromol/L or higher. Response to pre-operative chemotherapy was: 18% Grade I necrosis, 35% Grade II, 31% Grade III, and 16% Grade IV. No significant association was found between the mean peak MTX levels and necrosis (P = 0.44). Event-free survival (EFS) for the 48 patients with non-metastatic disease at diagnosis was 76% at 4 years of follow-up, with no association between the mean peak MTX level and EFS (P = 0.24). CONCLUSIONS: The absence of a demonstrable correlation between peak MTX levels and histologic necrosis or EFS may suggest that most patients achieve therapeutic levels when MTX is given at a dose of 12 g/m(2). The significant degree of intra-patient variability in peak levels poses a dilemma for pharmacokinetic adjustment. Continued use of HD-MTX in all patients, rather than dose adapted therapy, may be justified.