scholarly journals Advances in the Diagnosis and Treatment of Krabbe Disease

2021 ◽  
Vol 7 (3) ◽  
pp. 57
Author(s):  
David A Wenger ◽  
Paola Luzi ◽  
Mohammad A. Rafi
Keyword(s):  
Newborn Screening ◽  
Autosomal Recessive ◽  
Cultured Cells ◽  
Krabbe Disease ◽  
Hematopoietic Stem ◽  
Pathogenic Variants ◽  
Second Tier ◽  
Galc Gene ◽  
Hydrolysis Of

Krabbe disease is an autosomal recessive leukodystrophy caused by pathogenic variants in the galactocerebrosidase (GALC) gene. GALC activity is needed for the lysosomal hydrolysis of galactosylceramide, an important component of myelin. While most patients are infants, older patients are also diagnosed. Starting in 1970, a diagnosis could be made by measuring GALC activity in leukocytes and cultured cells. After the purification of GALC in 1993, the cDNA and genes were cloned. Over 260 disease-causing variants as well as activity lowering benign variants have been identified. While some pathogenic variants can be considered “severe,” others can be considered “mild.” The combination of alleles determines the type of Krabbe disease a person will have. To identify patients earlier, newborn screening (NBS) has been implemented in several states. Low GALC activity in this screening test may indicate a diagnosis of Krabbe disease. Second tier testing as well as neuro-diagnostic studies may be required to identify those individuals needing immediate treatment. Treatment of pre-symptomatic or mildly symptomatic patients at this time is limited to hematopoietic stem cell transplantation. Treatment studies using the mouse and dog models have shown that combining bone marrow transplantation with intra-venous gene therapy provides the best outcomes in terms of survival, behavior, and preservation of normal myelination in the central and peripheral nervous systems. With earlier diagnosis of patients through newborn screening and advances in treatment, it is hoped that more patients will have a much better quality of life.

scholarly journals Newborn Screening for Krabbe Disease—Illinois Experience: Role of Psychosine in Diagnosis of the Disease

2021 ◽  
Vol 7 (2) ◽  
pp. 24
Author(s):  
Khaja Basheeruddin ◽  
Rong Shao ◽  
Fran Balster ◽  
Pearlie Gardley ◽  
Laura Ashbaugh
Keyword(s):  
Newborn Screening ◽  
Late Onset ◽  
Population Based ◽  
Krabbe Disease ◽  
Reference Laboratory ◽  
Timely Manner ◽  
Second Tier ◽  
Galc Gene ◽  
Mass Spectrometry Assay

Population-based newborn screening for Krabbe disease was initiated by measurement of galactocerebrosidase (GALC) activity in the state of Illinois in December 2017. Due to the poor specificity of GALC for the diagnosis of Krabbe disease, second-tier testing services were provided to reduce the false positive rates for disease monitoring. Using ultra-pressure liquid chromatography coupled to mass spectrometry assay, a total of 497,147 newborns were screened. In total, 288 infants’ specimens (0.06%) having reduced GALC activity were sent out for second-tier testing to a reference laboratory. All newborns’ reduced GALC specimens were tested for psychosine levels, the presence of a 30-kb deletion and GALC sequencing. The results showed that two infants had elevated psychosine levels (10 and 35 nM) and were referred immediately for evaluation and treatment for Infantile Krabbe disease, and six infants had intermediate PSY levels (≥2 to 5 nM) and are under observation as suspected candidates for late-onset Krabbe disease. In addition, 178 infants had pseudodeficiency alleles, all having psychosine levels < 2.0 nM. Our data show that a high percentage of reduced GALC activity (62%) was due to the presence of pseudodeficiency alleles in the GALC gene. In conclusion, incorporation of psychosine measurements can identify infants with infantile Krabbe disease and probable late-onset Krabbe infants. Furthermore, Krabbe disease screening can be achieved at public health laboratories, and infants with infantile Krabbe disease can be diagnosed in timely manner for better outcome.

scholarly journals Can early treatment of twitcher mice with high dose AAVrh10-GALC eliminate the need for BMT?

Bioimpacts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 135-146
Author(s):  
Mohammad A Rafi ◽  
Paola Luzi ◽  
David A Wenger
Keyword(s):  
Gene Therapy ◽  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Viral Vector ◽  
Krabbe Disease ◽  
High Dose ◽  
Restriction Enzyme Digestion ◽  
Hematopoietic Stem ◽  
Galc Gene

Introduction: Krabbe disease (KD) is an autosomal recessive disorder caused by mutations in the galactocerebrosidase (GALC) gene resulting in neuro-inflammation and defective myelination in the central and peripheral nervous systems. Most infantile patients present with clinical features before six months of age and die before two years of age. The only treatment available for pre-symptomatic or mildly affected individuals is hematopoietic stem cell transplantation (HSCT). In the animal models, combining bone marrow transplantation (BMT) with gene therapy has shown the best results in disease outcome. In this study, we examine the outcome of gene therapy alone. Methods: Twitcher (twi) mice used in the study, have a W339X mutation in the GALC gene. Genotype identification of the mice was performed shortly after birth or post-natal day 1 (PND1), using polymerase chain reaction on the toe clips followed by restriction enzyme digestion and electrophoresis. Eight or nine-day-old affected mice were used for gene therapy treatment alone or combined with BMT. While iv injection of 4 × 1013 gc/kg of body weight of viral vector was used originally, different viral titers were also used without BMT to evaluate their outcomes. Results: When the standard viral dose was increased four- and ten-fold (4X and 10X) without BMT, the lifespans were increased significantly. Without BMT the affected mice were fertile, had the same weight and appearance as wild type mice and had normal strength and gait. The brains showed no staining for CD68, a marker for activated microglia/macrophages, and less astrogliosis than untreated twi mice. Conclusion: Our results demonstrate that, it may be possible to treat human KD patients with high dose AAVrh10 without blood stem cell transplantation which would eliminate the side effects of HSCT.

scholarly journals Prion-like α-synuclein pathology in the brains of infants: Krabbe disease as a novel seed-competent α-synucleinopathy

2021 ◽  
Author(s):  
Christopher Hatton ◽  
Simona S. Ghanem ◽  
David Koss ◽  
Ilham Yahya Abdi ◽  
Elizabeth Gibbons ◽  
...  
Keyword(s):  
Lewy Body ◽  
Neurodegenerative Disorder ◽  
Lewy Bodies ◽  
Krabbe Disease ◽  
Biological Processes ◽  
Pathogenic Variants ◽  
Increased Risk ◽  
Galc Gene ◽  
The Brain ◽  
Lewy Body Diseases

Krabbe disease (KD) is an infantile neurodegenerative disorder resulting from pathogenic variants in the GALC gene which causes accumulation of the toxic sphingolipid psychosine. GALC variants are associated with increased risk of Lewy body diseases (LBD), an umbrella term for age-associated neurodegenerative diseases in which the protein α-synuclein aggregates into Lewy bodies. To explore whether α-synuclein in KD has pathological similarities to that in LBD, we compared post-mortem KD tissue to that of infant control cases and identified alterations to α-synuclein localisation and expression of modifications associated with LBD. To determine whether α-synuclein in KD displayed pathogenic properties associated with LBD we evaluated its seeding capacity using the real-time quaking-induced conversion assay. Strikingly, seeded aggregation of α-synuclein resulted in the formation of fibrillar aggregates similar to those observed in LBD, confirming the prion-like capacity of KD-derived α-synuclein. These observations constitute the first report of prion-like α-synuclein in the brain tissue of infants and challenge the putative view that α-synuclein pathology is merely an age-associated phenomenon, instead suggesting it can result from alterations to biological processes such as sphingolipid homeostasis. Our findings have important implications for understanding the mechanisms underlying Lewy body formation in LBD.

Clinical and molecular characteristics and time of diagnosis of patients with classical galactosemia in an unscreened population in Turkey

2019 ◽  
Vol 32 (7) ◽  
pp. 675-681
Author(s):  
Pelin Teke Kisa ◽  
Melis Kose ◽  
Ozlem Unal ◽  
Esra Er ◽  
Burcu Ozturk Hismi ◽  
...  
Keyword(s):  
Newborn Screening ◽  
Autosomal Recessive ◽  
Screening Program ◽  
Clinical Manifestations ◽  
Geographical Location ◽  
Molecular Characteristics ◽  
Phenotype Correlation ◽  
Classical Galactosemia ◽  
Pathogenic Variants ◽  
Turkish Patients

Abstract Classical galactosemia is an autosomal recessive inborn error of metabolism caused by biallelic pathogenic variants in the GALT gene. With the benefit of early diagnosis by newborn screening, the acute presentation of galactosemia can be prevented. In this study, we describe the clinical phenotypes, time of diagnosis and GALT genotypes of 76 galactosemia patients from Turkey, where the disease is not yet included in the newborn screening program. The median age at first symptom was 10 days (range 5–20), while the median age at diagnosis was 30 days (range 17–53). Nearly half of the patients (36 patients, 47.4%) were diagnosed later than age 1 month. Fifty-eight individuals were found to have 18 different pathogenic variants in their 116 mutant alleles. In our sample, Q188R variant has the highest frequency with 53%, the other half of the allele frequency of the patients showed 17 different genotypes. Despite presenting with typical clinical manifestations, classical galactosemia patients are diagnosed late in Turkey. Due to the geographical location of our country, different pathogenic GALT variants may be seen in Turkish patients. In the present study, a clear genotype-phenotype correlation could not be established in patients.

scholarly journals Compound heterozygous pathogenic variants in the GALC gene cause infant-onset Krabbe disease

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Xiaoli Zhang ◽  
Guohui Niu ◽  
Panpan Song ◽  
Lijun Wang ◽  
Rui Han ◽  
...  
Keyword(s):  
Krabbe Disease ◽  
Compound Heterozygous ◽  
Pathogenic Variants ◽  
Galc Gene

scholarly journals Molecular diagnostics of the Krabbe disease in Russian children

2020 ◽  
Vol 1 (1) ◽  
pp. 21-28
Author(s):  
Alexander A. Pushkov ◽  
Nataliya N. Mazanova ◽  
Lyudmila M. Kuzenkova ◽  
Nataliya V. Zhurkova ◽  
Oksana V. Globa ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Molecular Diagnostics ◽  
High Efficiency ◽  
Molecular Genetic ◽  
Krabbe Disease ◽  
Control Group ◽  
Laboratory Diagnostics ◽  
Lysosomal Storage ◽  
Pathogenic Variants ◽  
Galc Gene

Introduction. Krabbe disease (KD) is the lysosomal storage disease developed due to the decline of the galactocerebrosidase activity associated with mutations in the GALC gene. It leads to the development of oligodendrocytes and lemmocytes (Schwann cells) myelin-forming dysfunction. Nowadays the only possible treatment of KD is hemopoietic cell transplantation which should be performed before the manifestation of any signs of disease. That is why laboratory diagnostics has special significance. The aim of the study. To elaborate the algorithm of a molecular diagnostics of the Krabbe disease (KD) in Russian children. Material and methods. 190 patients were diagnosed for the exclusion of KD during the period from 2012 to 2019. In all cases, there was measured a galactocerebrosidase activity in dry blood spots. In cases with the declined enzyme activity, there was performed a further search of pathogenic variants in the GALC gene. The concentration of glycosyl sphingosine (Lyso-GL1) biomarker was measured in 90 patients included in the study since 2016. Results. The enzyme activity was decreased in all patients in comparison with the control group (0.330.05; 2.950.24 mol/l/h, (p0.001; CI: 95%) in 9 patients. Also, we revealed an increased concentration of Lyso-GL1 biomarker in matched controls (12.501.57 ng/ml; 1.80.33 ng/ml, (p0.005; CI: 95%) in 5 patients. During molecular genetic testing of KD, three novel pathogenic variants of the GALC gene were revealed in 3 out of 9 patients: c.265-2AG, c.1036del and c.2037_2040del. Conclusion. The Lyso-GL1 concentration measurement can be used as an additional diagnostics method of KD. The high efficiency of the presented algorithm for the KD diagnostics in Russian children is presented.

scholarly journals Compound Galactosylceramidase Gene (GALC) Heterozygosity in a Boy with Infantile Krabbe Disease (KD)

PRILOZI ◽  
2015 ◽  
Vol 36 (3) ◽  
pp. 99-101 ◽  
Author(s):  
Zoran Gucev ◽  
Velibor Tasic
Keyword(s):  
Autosomal Recessive ◽  
Storage Disease ◽  
Clinical Course ◽  
Compound Heterozygote ◽  
Krabbe Disease ◽  
Lysosomal Storage ◽  
Mental Deterioration ◽  
Severe Motor ◽  
Galc Gene ◽  
Globoid Cell

Abstract Krabbe disease (KD) (globoid cell leukodystrophy) is a degenerative, lysosomal storage disease, caused by a severe loss of galactocerebrosidase (GALC) enzymatic activity. The inheritance is autosomal recessive. KD affects the white matter of the central and peripheral nervous systems. We present a 3 year old boy in whom the disease had an ‘infantile’ or ‘classic’ presentation, with spasticity, irritability, and developmental delay. In addition the boy showed progressive severe motor and mental deterioration, difficulties in swallowing and decerebration. Molecular analysis revealed that the child is a compound heterozygote: p.Asp187Val (c.560A>T) and p.Ile250Thr (c.749T>C). The father was the carrier of p.Asp187Val (c.560A>T), while the mother was the carrier of the p.Ile250Thr (c.749T>C) in exon 6 of the GALC gene. The clinical course in this compound heterozygote is severe and the patient passed away at the age of 3 years. Genotype-phenotype relations are discussed in this Macedonian patient with KD.

scholarly journals Family Attitudes regarding Newborn Screening for Krabbe Disease: Results from a Survey of Leukodystrophy Registries

2020 ◽  
Vol 6 (3) ◽  
pp. 66
Author(s):  
Karlita Blackwell ◽  
Michael H. Gelb ◽  
Anna Grantham ◽  
Natasha Spencer ◽  
Christin Webb ◽  
...  
Keyword(s):  
Stem Cell ◽  
Newborn Screening ◽  
Krabbe Disease ◽  
Hematopoietic Stem ◽  
Family Attitudes ◽  
Family Perspective ◽  
The Usa ◽  
History Of ◽  
Cell Transplantation Therapy ◽  
Transplantation Therapy

Newborn screening (NBS) for Krabbe disease (KD) is currently underway in eight states in the USA, and there is continued discussion of whether to implement KD NBS in additional states. Workgroup members sought to survey a large number of families affected by KD. Families in KD and leukodystrophy family registries were contacted to seek their participation in The Krabbe Newborn Screening—Family Perspective Survey. The 170 respondents are comprised of the following: 138 family members with a KD individual diagnosed after development of symptoms, 20 notified about KD via NBS, and 12 with a KD individual diagnosed through family history of KD. The key results are that all NBS families with an early-infantile KD family member elected to pursue hematopoietic stem cell transplantation therapy. Of the 170 responders, 165 supported the implementation of KD NBS in all states in the USA.

scholarly journals The combined use of enzyme activity and metabolite assays as a strategy for newborn screening of mucopolysaccharidosis type I

2020 ◽  
Vol 58 (12) ◽  
pp. 2063-2072 ◽  
Author(s):  
Giulia Polo ◽  
Daniela Gueraldi ◽  
Antonella Giuliani ◽  
Laura Rubert ◽  
Chiara Cazzorla ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Newborn Screening ◽  
False Positives ◽  
Type I ◽  
Mucopolysaccharidosis Type ◽  
Mucopolysaccharidosis Type I ◽  
Hematopoietic Stem ◽  
Enzyme Replacement ◽  
Second Tier ◽  
Mps I

AbstractObjectivesMucopolysaccharidosis type I (MPS I) was added to our expanded screening panel in 2015. Since then, 127,869 newborns were screened by measuring α-L-iduronidase (IDUA) enzyme activity with liquid chromatography tandem mass spectrometry (LC-MS/MS). High false positives due to frequent pseudodeficiency alleles prompted us to develop a second-tier test to quantify glycosaminoglycan (GAG) levels in dried blood spot (DBS).MethodsHeparan-sulfate (HS) and dermatan-sulfate (DS) were measured with LC-MS/MS after methanolysis. DBSs were incubated with methanolic-HCl 3 N at 65 °C for 45 min. Chromatographic separation used an amide column with a gradient of acetonitrile and water with 10 mM ammonium acetate in a 9-min run. The method was validated for specificity, linearity, lower limit of quantification (LOQ), accuracy and precision.ResultsIntra- and inter-day coefficients of variation were <15% for both metabolites. Reference values in 40 healthy newborns were: HS mean 1.0 mg/L, 0–3.2; DS mean 1.5 mg/L, 0.5–2.7). The two confirmed newborn MPS I patients had elevated HS (4.9–10.4 mg/L, n.v. <3.2) and DS (7.4–8.8 mg/L, n.v. <2.7). Since its introduction in February 2019, the second-tier test reduced the recall rate from 0.046% to 0.006%. Among 127,869 specimens screened, the incidence was 1:63,935 live births. Both patients started enzyme replacement therapy (ERT) within 15 days of birth and one of them received allogenic hematopoietic stem cell transplantation (HSCT) at ht age of 6 months.ConclusionsGAGs in DBS increased the specificity of newborn screening for MPS I by reducing false-positives due to heterozygosity or pseudodeficiency. Early diagnosis and therapeutical approach has improved the outcome of our patients with MPS I.

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