Mutations and polymorphisms of the alpha-galactosidase A gene in patients with hypertrophic...
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Fabry disease is a lysosomal disorder whose causes are mutations in the GLA gene, mapped in the human X chromosome (Xq22). Such mutations result either in the incapacity of the enzyme entering the lysosome or the reduction/elimination of the activity of the α- galactosidase A (α-GAL) enzyme, whose function is to metabolize intralysosomal glycosphingolipids, e.g. globotriaosylceramide (Gb3), the major lipid accumulated in the lysosomes in FD. The appearance of renal disease in these patients is among the consequences of the accumulation of Gb3. Recent studies show that podocyte is the most affected renal cell in the disease and whose response is the most difficult to the enzyme replacement therapy. On the other hand, it is the cell responsible for the progressive loss of the renal function and is found altered even before we have microalbuminuria. As physiologically there is excretion of podocytes in the urine, determining the podocyturia in FD is an interesting element to predict renal disease. The objective of our study was to quantify the excretion of urinary podocytes in FD patients with a classic Fabry genotype (V269M, n = 13) with eGFR range from normal to reduced and healthy controls (n = 40), and to correlate them with the variables gender, age treatment time and albumin:creatinine ratio (ACR). Fresh urine sampled immediately after first urination in the morning was used. Urinary podocytes were stained using an immuno- fluorescence technique to podocalyxin and DAPi on laminas. The number of podocalyxin-positive cells was counted by two medical technicians and the mean of the number was taken (normal range 0-0.8 podocytes/ mL). From the 14 samples analyzed, 7 came from males and 7 from females, the age ranged from 8-74 years and the treatment time with algasidase alpha from 0-24 months. The mean of podocytes in urine of FD patients was significantly higher than in healthy controls (p b 0.0001). The correlation podocyturia/ACR was positive and statis- tically significant (p = 0.004). There was no correlation of podocyturia with gender, age and time of treatment. Podocyturia is an important parameter in the assessment of renal disease in general, and it may serve as an additional early laboratory examination for monitoring FD nephropaty before altered ACR modifying, thereafter, the natural history of the disease in patients expected to have a more aggressive phenotype. This work was supported by a grant from Shire. doi:10.1016/j.ymgme.2013.12.206 195 Mutations and polymorphisms of the alpha-galactosidase A gene in patients with hypertrophic cardiomyopathy Stefan Pfaffenberger, Natalija Lajic, Martina Gaggl, Anita Jallitsch- Halper, Sabine Scherzer, Jolanta Siller-Matula, Raphael Rosenhek, Till Voigtlaender, Raute Sunder-Plassmann, Gere Sunder-Plassmann, Gerald Mundigler, Medical University Vienna, Vienna, Austria Background: Anderson-Fabry disease (AFD) is a rare cause of hypertrophic cardiomyopathies (HCM). Clinical signs alone do not allow distinguishing a cardiac manifestation of AFD from sarcomeric forms of HCM. Enzyme activity analysis and genetic testing of the α-galactosidase A(α-GAL) gene (GLA) are therefore important for diagnosis and verification of disease causing mutations. Design: Prospective cross-sectional single centre study. Patients: We enrolled 108 adults (76 males, 32 females) with a referral diagnosis of HCM with a left ventricular wall thickness of ≥15 mm on echocardiography. Main outcome measures Laboratory analyses included the measurement of α-GAL activity in leukocytes and sequencing of the GLA gene in all patients. Symptoms were evaluated using a specified questionnaire. Results: Mutation analyses confirmed AFD in two patients (p.G35R and g.5092A N G; 1.9%). One female patient (0.98%) had a rare polymorphism (p.D313Y) previously described as disease causing for AFD. In 31 patients (28.7%) various combinations of polymorphisms were detected. The g.1170C N T polymorphism was found in 9 patients (7 males) and was associated with a significantly decreased α-GAL activity in leukocytes among male subjects compared to the wild type GLA gene (p = 0.003). Clinically these patients showed higher frequen- cies of non-sustained ventricular tachycardias (nsVTs, p = 0.009). Conclusions: Specific testing of the GLA gene in patients with HCM confirmed AFD in two patients and revealed various polymorphisms in almost one third of patients. The g.1170C N T polymorphism was found in 8% and is associated with a reduced α-GAL activity and a higher incidence of nsVTs in males. doi:10.1016/j.ymgme.2013.12.207 196 Hereditary spastic paraplegias types 15 and 11 are associated with lysosomal abnormalities Tyler Mark Pierson a , Benoît Renvoisé b , Jaerak Chang b , Camilo Toro c , Craig Blackstone b , a Cedars-Sinai Medical Center, Los Angeles, CA, USA, b NINDS/NIH, Bethesda, MD, USA, c NHGRI/NIH, Bethesda, MD, USA The hereditary spastic paraplegias (HSP) are among the most genetically diverse inherited neurological disorders with over 50 distinct disease loci identified to date. The identification of cellular themes common among the HSP is important for understanding disease pathogenesis. SPG15 involves mutations in SPG15 (aka ZFYVE26) encoding spastizin (aka FYVE-CENT), while SPG11 is caused by mutations in the SPG11 gene affecting the spatacsin protein. We investigated SPG15-related cellular changes in patient fibroblasts, seeking to identify shared pathogenic themes between SPG15 and SPG11. These two clinically-similar disorders are the most common autosomal recessive forms of HSP, and are characterized clinically by progressive spastic paraplegia along with a thin corpus callosum, white matter abnormal- ities, progressive cognitive impairment, lenticular opacities, and retinal storage. Furthermore, both have been linked to early-onset Parkinsonism. Fibroblast cell lines prepared from different patients with SPG15 had selective enlargement of lysosomal size and consistently showed abnormal lysosomal storage by electron microscopy. Lysosomal enlarge- ment was also observed in cell lines from multiple patients with SPG11, though prominent abnormal lysosomal storage was not observed. The stability of the SPG15 protein, spastizin, and the SPG11 protein, spatacsin, were highly dependent upon one another's presence. Emerging studies implicating these two proteins in interactions with the late endosomal/ lysosomal adaptor protein complex AP-5 are consistent with their similar abnormalities in the sizes of lysosomes suggesting a converging mechanism for these two disorders involving the lysosome. doi:10.1016/j.ymgme.2013.12.208 197 TNF-α levels are increased in children with mucopolysaccharidosis types I, II, and VI treated with ERT Lynda E. Polgreen, Richard Vehe, Kyle Rudser, Alicia Kunin-Batson, Jeanine Utz, Elsa Shapiro, Chester B. Whitley, University of Minnesota, Minneapolis, MN, USA Despite treatment with enzyme replacement therapy (ERT), the majority of individuals with mucopolysaccharidosis (MPS) type I, II or VI report significant decreased physical function and pain. In animal models of MPS, tumor necrosis factor - alpha (TNF-α) levels are increased and treatment with TNF-α inhibitors improve physical function. Therefore, Abstracts S86
Transcript of Mutations and polymorphisms of the alpha-galactosidase A gene in patients with hypertrophic...
Fabry disease is a lysosomal disorder whose causes are mutations inthe GLA gene, mapped in the human X chromosome (Xq22). Suchmutations result either in the incapacity of the enzyme entering thelysosome or the reduction/elimination of the activity of the α-galactosidase A (α-GAL) enzyme, whose function is to metabolizeintralysosomal glycosphingolipids, e.g. globotriaosylceramide (Gb3), themajor lipid accumulated in the lysosomes in FD. The appearance of renaldisease in these patients is among the consequences of the accumulationof Gb3. Recent studies show that podocyte is the most affected renal cellin the disease and whose response is the most difficult to the enzymereplacement therapy. On the other hand, it is the cell responsible fortheprogressive loss of the renal function and is found altered even beforewe have microalbuminuria. As physiologically there is excretion ofpodocytes in the urine, determining the podocyturia in FD is aninteresting element to predict renal disease. The objective of our studywas to quantify the excretion of urinary podocytes in FD patients with aclassic Fabry genotype (V269M, n= 13) with eGFR range from normalto reduced andhealthy controls (n = 40), and to correlate themwith thevariables gender, age treatment time and albumin:creatinine ratio(ACR). Fresh urine sampled immediately after first urination in themorning was used. Urinary podocytes were stained using an immuno-fluorescence technique to podocalyxin andDAPi on laminas. The numberof podocalyxin-positive cells was counted by two medical techniciansand the mean of the number was taken (normal range 0-0.8 podocytes/mL). From the 14 samples analyzed, 7 came from males and 7 fromfemales, the age ranged from 8-74 years and the treatment time withalgasidase alpha from 0-24 months. The mean of podocytes in urine ofFD patients was significantly higher than in healthy controls(p b 0.0001). The correlation podocyturia/ACR was positive and statis-tically significant (p = 0.004). There was no correlation of podocyturiawith gender, age and time of treatment. Podocyturia is an importantparameter in the assessment of renal disease in general, and itmay serveas an additional early laboratory examination for monitoring FDnephropaty before altered ACRmodifying, thereafter, the natural historyof the disease in patients expected to have amore aggressive phenotype.This work was supported by a grant from Shire.
doi:10.1016/j.ymgme.2013.12.206
195Mutations and polymorphisms of the alpha-galactosidase A genein patients with hypertrophic cardiomyopathy
Stefan Pfaffenberger, Natalija Lajic, Martina Gaggl, Anita Jallitsch-Halper, Sabine Scherzer, Jolanta Siller-Matula, Raphael Rosenhek, TillVoigtlaender, Raute Sunder-Plassmann, Gere Sunder-Plassmann,Gerald Mundigler, Medical University Vienna, Vienna, Austria
Background: Anderson-Fabry disease (AFD) is a rare cause ofhypertrophic cardiomyopathies (HCM). Clinical signs alone do not allowdistinguishing a cardiac manifestation of AFD from sarcomeric forms ofHCM. Enzyme activity analysis and genetic testing of theα-galactosidaseA (α-GAL) gene (GLA) are therefore important for diagnosis andverification of disease causing mutations.
Design: Prospective cross-sectional single centre study.Patients: We enrolled 108 adults (76 males, 32 females) with a
referral diagnosis of HCM with a left ventricular wall thickness of≥15 mm on echocardiography. Main outcome measures Laboratoryanalyses included the measurement of α-GAL activity in leukocytesand sequencing of the GLA gene in all patients. Symptoms wereevaluated using a specified questionnaire.
Results: Mutation analyses confirmed AFD in two patients (p.G35Rand g.5092A N G; 1.9%). One female patient (0.98%) had a rarepolymorphism (p.D313Y) previously described as disease causing for
AFD. In 31 patients (28.7%) various combinations of polymorphismswere detected. The g.1170C N T polymorphism was found in 9 patients(7 males) and was associated with a significantly decreased α-GALactivity in leukocytes among male subjects compared to the wild typeGLA gene (p = 0.003). Clinically these patients showed higher frequen-cies of non-sustained ventricular tachycardias (nsVTs, p = 0.009).
Conclusions: Specific testing of the GLA gene in patients with HCMconfirmed AFD in two patients and revealed various polymorphismsin almost one third of patients. The g.1170C N T polymorphism wasfound in 8% and is associated with a reduced α-GAL activity and ahigher incidence of nsVTs in males.
doi:10.1016/j.ymgme.2013.12.207
196Hereditary spastic paraplegias types 15 and 11 are associated withlysosomal abnormalities
Tyler Mark Piersona, Benoît Renvoiséb, Jaerak Changb, Camilo Toroc,Craig Blackstoneb, aCedars-Sinai Medical Center, Los Angeles, CA, USA,bNINDS/NIH, Bethesda, MD, USA, cNHGRI/NIH, Bethesda, MD, USA
The hereditary spastic paraplegias (HSP) are among the mostgenetically diverse inherited neurological disorders with over 50 distinctdisease loci identified to date. The identification of cellular themescommon among the HSP is important for understanding diseasepathogenesis. SPG15 involves mutations in SPG15 (aka ZFYVE26)encoding spastizin (aka FYVE-CENT),while SPG11 is caused bymutationsin the SPG11 gene affecting the spatacsin protein. We investigatedSPG15-related cellular changes in patient fibroblasts, seeking to identifyshared pathogenic themes between SPG15 and SPG11. These twoclinically-similar disorders are the most common autosomal recessiveforms of HSP, and are characterized clinically by progressive spasticparaplegia along with a thin corpus callosum, white matter abnormal-ities, progressive cognitive impairment, lenticular opacities, and retinalstorage. Furthermore, both have been linked to early-onset Parkinsonism.Fibroblast cell lines prepared from different patients with SPG15had selective enlargement of lysosomal size and consistently showedabnormal lysosomal storage by electron microscopy. Lysosomal enlarge-ment was also observed in cell lines from multiple patients with SPG11,though prominent abnormal lysosomal storage was not observed. Thestability of the SPG15 protein, spastizin, and the SPG11 protein, spatacsin,were highly dependent upon one another's presence. Emerging studiesimplicating these two proteins in interactions with the late endosomal/lysosomal adaptor protein complex AP-5 are consistentwith their similarabnormalities in the sizes of lysosomes suggesting a convergingmechanism for these two disorders involving the lysosome.
doi:10.1016/j.ymgme.2013.12.208
197TNF-α levels are increased in children with mucopolysaccharidosistypes I, II, and VI treated with ERT
Lynda E. Polgreen, Richard Vehe, Kyle Rudser, Alicia Kunin-Batson,Jeanine Utz, Elsa Shapiro, Chester B. Whitley, University of Minnesota,Minneapolis, MN, USA
Despite treatment with enzyme replacement therapy (ERT), themajority of individuals with mucopolysaccharidosis (MPS) type I, II or VIreport significant decreased physical function andpain. In animalmodelsof MPS, tumor necrosis factor - alpha (TNF-α) levels are increased andtreatment with TNF-α inhibitors improve physical function. Therefore,
AbstractsS86
