Newborn screening for Fabry disease in Japan: prevalence and genotypes of Fabry disease in a pilot study

Elevated Inflammatory Plasma Biomarkers in Patients With Fabry Disease: A Critical Link to Heart Failure With Preserved Ejection Fraction

Background Because systemic inflammation and endothelial dysfunction lead to heart failure with preserved ejection fraction, we characterized plasma levels of inflammatory and cardiac remodeling biomarkers in patients with Fabry disease ( FD ). Methods and Results Plasma biomarkers were studied in multicenter cohorts of patients with FD (n=68) and healthy controls (n=40). Plasma levels of the following markers of inflammation and cardiac remodeling were determined: tumor necrosis factor ( TNF ), TNF receptor 1 ( TNFR 1) and 2 ( TNFR 2), interleukin-6, matrix metalloprotease-2 ( MMP -2), MMP -8, MMP -9, galectin-1, galectin-3, B-type natriuretic peptide ( BNP ), midregional pro-atrial natriuretic peptide ( MR -pro ANP ), and globotriaosylsphingosine. Clinical profile, cardiac magnetic resonance imaging, and echocardiogram were reviewed and correlated with biomarkers. Patients with FD had elevated plasma levels of BNP , MR -pro ANP , MMP -2, MMP -9, TNF , TNFR 1, TNFR 2, interleukin-6, galectin-1, globotriaosylsphingosine, and analogues. Plasma TNFR 2, TNF , interleukin-6, MMP -2, and globotriaosylsphingosine were elevated in FD patients with left ventricular hypertrophy, whereas diastolic dysfunction correlated with higher BNP , MR -pro ANP , and MMP -2 levels. Patients with late gadolinium enhancement on cardiac magnetic resonance imaging had greater levels of BNP , MR -pro ANP , TNFR 1, TNFR 2, and MMP -2. Plasma BNP , MR -pro ANP , MMP -2, MMP -8, TNF , TNFR 1, TNFR 2, galectin-1, and galectin-3 were elevated in patients with renal dysfunction. Patients undergoing enzyme replacement therapy who have more severe disease had higher MMP -2, TNF , TNFR 1, TNFR 2, and globotriaosylsphingosine analogue levels. Conclusions Inflammatory and cardiac remodeling biomarkers are elevated in FD patients and correlate with disease progression. These features are consistent with a phenotype dominated by heart failure with preserved ejection fraction and suggest a key pathogenic role of systemic inflammation in FD .

Fabry disease in a Japanese population-molecular and biochemical characteristics

We had experienced 117 Japanese Fabry patients (72 males and 45 females) from 1977 to 2006, and then we generated an improved Fabry analysis system in 2007 and have found 196 ones (95 males and 101 females) since then. In this study, we summarized the data of the patients and tried to elucidate the molecular and biochemical characteristics of Japanese Fabry patients. Gene analysis revealed various GLA mutations, including missense mutations (56.5%, 48 types); nonsense mutations (15.9%, 13 types); deletions (12.6%, 13 types); splicing defects (10.1%, 6 types); insertions (1.0%, 2 types), and insertions/deletions (0.5%, 1 type), in the patients that were tested. Amino acid substitutions resulting from the missense mutations found in the classic form patients tended to be localized in the core of the GLA protein, and those in the later-onset ones in the peripheral region. The most commonly identified pathogenic mutations are c.888G > A (p.M296I), c.936 + 919G > A, c.679C > T (p.R227X), c.335G > A (p.R112H), c.334C > T (p.R112C), and c.902G > A (p.R301Q). Among them, c.888G > A (p.M296I) is unique to Japanese Fabry patients. On the other hand, c.936 + 919G > A is a variant that has been frequently detected in Taiwan Chinese Fabry patients, and c.335G > A (p.R112H) in various countries. These are found in later-onset patients, and c.679C > T (p.R227X) and c.334C > T (p.R112C) classic ones. c.902G > A (p.R301Q) is found in both classic and later-onset form patients. A possible functional polymorphism, c.196G > C (p.E66Q), was identified in 0.4% of the subjects who underwent high-risk screening. The biochemical findings including leukocyte α-galactosidase A activity, plasma globotriaosylsphingosine level and urinary globotriaosylceramide in the individual phenotypic groups well reflected the phenotypic differences in this disease. The results will be useful for understanding the basis of Fabry disease in Japan.

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The characteristics of Japanese Fabry patients were elucidated.

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p.M296I unique to Japanese Fabry patients was commonly identified.

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The biochemical findings well reflected the phenotypic differences.

Non-clinical evaluation of JR-051 as a biosimilar to agalsidase beta for the treatment of Fabry disease

Fabry disease (FD) is an X-linked lysosomal storage disease. It is caused by deficiency of the enzyme α-galactosidase A (α-Gal A), which leads to excessive deposition of neutral glycosphingolipids, especially globotriaosylceramide (GL-3), in cells throughout the body. Progressive accumulation of GL-3 causes life-threatening complications in several tissues and organs, including the vasculature, heart, and kidney. Currently available enzyme replacement therapy for FD employs recombinant α-Gal A in two formulations, namely agalsidase alfa and agalsidase beta. Here, we evaluated JR-051 as a biosimilar to agalsidase beta in a non-clinical study. JR-051 was shown to have identical primary and similar higher-order structures to agalsidase beta. Mannose-6-phosphate content was higher in JR-051 than in agalsidase beta, which probably accounts for a slightly better uptake into fibroblasts in vitro. In spite of these differences in in vitro biological features, pharmacokinetic profiles of the two compounds in mice, rats, and monkeys were similar. The ability to reduce GL-3 accumulation in the kidney, heart, skin, liver, spleen, and plasma of Gla-knockout mice, a model of FD, was not different between JR-051 and agalsidase beta. Furthermore, we identified no safety concerns regarding JR-051 in a 13-week evaluation using cynomolgus monkeys. These findings indicate that JR-051 is similar to agalsidase beta in terms of physicochemical and biological properties.

The New York pilot newborn screening program for lysosomal storage diseases: Report of the First 65,000 Infants

Purpose:

We conducted a consented pilot newborn screening (NBS) for Pompe, Gaucher, Niemann Pick A/B, Fabry, and MPS 1 to assess the suitability of these lysosomal storage disorders (LSD) for public health mandated screening.

Methods:

At five participating high-birth-rate, ethnically diverse New York City hospitals, recruiters discussed the study with post-partum parents and documented verbal consent. Screening on consented samples was performed using multiplexed tandem mass spectrometry. Screen-positive infants underwent confirmatory enzymology, DNA testing, and biomarker quantitation when available. Affected infants are being followed for clinical management and long term outcome.

Results:

65,605 infants participated over four years, representing an overall consent rate of 74%. Sixty-nine infants were screen-positive. Twenty-three were confirmed true positives, all of whom were predicted to have late-onset phenotypes. Six of the 69 currently have undetermined disease status.

Conclusion:

Our results suggest that NBS for LSDs is much more likely to detect individuals at risk for late-onset disease, similar to results from other NBS programs. This work has demonstrated the feasibility of using a novel consented pilot NBS study design that can be modified to include other disorders under consideration for public health implementation as a means to gather critical evidence for evidence-based NBS practices.

Improvement in the sensitivity of newborn screening for Fabry disease among females through the use of a high-throughput and cost-effective method, DNA mass spectrometry

Many female carriers of Fabry disease are likely to develop severe morbidity and mortality. However, by our own estimation, around 80% of female newborns are missed by our current enzyme-based screening approach. Our team's aim was to develop an improved cost-effective screening method that is able to detect Fabry disease among female newborns. In Taiwan, based on a database of 916,000 newborns, ~98% of Fabry patients carry mutations out of a pool of only 21 pathogenic mutations. An Agena iPLEX platform was designed to detect these 21 pathogenic mutations using only a single-assay panel. A total of 54,791 female infants were screened and 136 female newborns with the IVS4 + 919G > A mutation and one female newborn with the c.656T > C mutation were identified. Using the current enzyme-based newborn screening approach as baseline, around 83% of female newborns are being missed. Through a family study of the IVS4 female newborns, 30 IVS4 adult family members were found to have left ventricular hypertrophy. Ten patients received endomyocardial biopsy and all were found to have significant globotriaosylceramide (Gb3) accumulation in their cardiomyocytes. All of these individuals now receive enzyme replacement therapy. We have demonstrated that the Agena iPLEX assay is a powerful tool for detecting females with Fabry disease. Furthermore, through this screening, we also have been able to identify many disease-onset adult family members who were originally undiagnosed for Fabry disease. This screening helps them to receive treatment in time before severe and irreversible cardiac damage has occurred.

Human dorsal root ganglion in vivo morphometry and perfusion in Fabry painful neuropathy

Objective:

To evaluate functional and morphometric magnetic resonance neurography of the dorsal root ganglion and peripheral nerve segments in patients with Fabry painful neuropathy.

Methods:

In this prospective study, the lumbosacral dorsal root ganglia and proximal peripheral nerve segments of the lower extremity were examined in 11 male patients with Fabry disease by a standardized 3T magnetic resonance neurography protocol. Volumes of L3 to S2 dorsal root ganglia, perfusion parameters of L5-S1 dorsal root ganglia and the spinal nerve L5, and the cross-sectional area of the proximal sciatic nerve were compared to healthy controls.

Results:

Dorsal root ganglia of patients with Fabry disease were symmetrically enlarged by 78% (L3), 94% (L4), 122% (L5), 115% (S1), and 119% (S2) (p < 0.001). In addition, permeability of the blood-tissue interface was decreased by 53% (p < 0.001). This finding was most pronounced in the peripheral zone of the dorsal root ganglion containing the cell bodies of the primary sensory neurons (p < 0.001). Spinal nerve permeability showed no difference between patients with Fabry disease and controls (p = 0.7). The sciatic nerve of patients with Fabry disease at the thigh level showed an increase in cross-sectional area by 48% (p < 0.001).

Conclusions:

Patients with Fabry disease have severely enlarged dorsal root ganglia with dysfunctional perfusion. This may be due to glycolipid accumulation in the dorsal root ganglia mediating direct neurotoxic effects and decreased neuronal blood supply. These alterations were less pronounced in peripheral nerve segments. Thus, the dorsal root ganglion might play a key pathophysiologic role in the development of neuropathy and pain in Fabry disease.

Clinical characteristics and mutation spectrum of GLA in Korean patients with Fabry disease by a nationwide survey: Underdiagnosis of late-onset phenotype

Fabry disease is a rare X-linked lysosomal storage disorder caused by an α-galactosidase A deficiency. The progressive accumulation of globotriaosylceramide (GL-3) results in life-threatening complications, including renal, cardiac, and cerebrovascular diseases. This study investigated the phenotypic and molecular spectra of GLA mutations in Korean patients with Fabry disease using a nationwide survey.This study included 94 patients from 46 independent pedigrees: 38 adult males, 46 symptomatic females, and 10 pediatric males. Each diagnosis was based on an enzyme assay and GLA gene mutation analysis.The mean age at presentation was 24 years (range, 5-65 years); however, the diagnoses were delayed by 21 ± 19 years after the onset of symptoms. Those patients with late-onset Fabry disease were diagnosed by family screening or milder symptoms at a later age. Forty different mutations were identified: 20 missense (50%), 10 nonsense (25%), 8 frameshift (20%), and 2 splice site (5%) mutations. Five of them were novel. IVS4+919G>A (c.936+919 G>A) was not detected among the 6505 alleles via newborn screening using dried blood spots. Enzyme replacement therapy (ERT) was performed in all the males and pediatric patients, whereas 75% of the symptomatic females underwent ERT for 4.2 ± 3.6 years.This study described the demographic data, wide clinical spectrum of phenotypes, and GLA mutation spectrum of Fabry disease in Korea. Most of the patients had classical Fabry disease, with a 4 times higher incidence than that of late-onset Fabry disease, indicating an underdiagnosis of mild, late-onset Fabry disease.

Lentivector Iterations and Pre-Clinical Scale-Up/Toxicity Testing: Targeting Mobilized CD34+ Cells for Correction of Fabry Disease

Fabry disease is a rare lysosomal storage disorder (LSD). We designed multiple recombinant lentivirus vectors (LVs) and tested their ability to engineer expression of human α-galactosidase A (α-gal A) in transduced Fabry patient CD34⁺ hematopoietic cells. We further investigated the safety and efficacy of a clinically directed vector, LV/AGA, in both ex vivo cell culture studies and animal models. Fabry mice transplanted with LV/AGA-transduced hematopoietic cells demonstrated α-gal A activity increases and lipid reductions in multiple tissues at 6 months after transplantation. Next we found that LV/AGA-transduced Fabry patient CD34⁺ hematopoietic cells produced even higher levels of α-gal A activity than normal CD34⁺ hematopoietic cells. We successfully transduced Fabry patient CD34⁺ hematopoietic cells with “near-clinical grade” LV/AGA in small-scale cultures and then validated a clinically directed scale-up transduction process in a GMP-compliant cell processing facility. LV-transduced Fabry patient CD34⁺ hematopoietic cells were subsequently infused into NOD/SCID/Fabry (NSF) mice; α-gal A activity corrections and lipid reductions were observed in several tissues 12 weeks after the xenotransplantation. Additional toxicology studies employing NSF mice xenotransplanted with the therapeutic cell product demonstrated minimal untoward effects. These data supported our successful clinical trial application (CTA) to Health Canada and opening of a “first-in-the-world” gene therapy trial for Fabry disease.

Newborn screening for six lysosomal storage disorders in a cohort of Mexican patients: Three-year findings from a screening program in a closed Mexican health system

OBJECTIVE

To evaluate the results of a lysosomal newborn screening (NBS) program in a cohort of 20,018 Mexican patients over the course of 3years in a closed Mexican Health System (Petróleos Mexicanos [PEMEX] Health Services).

STUDY DESIGN

Using dried blood spots (DBS), we performed a multiplex tandem mass spectrometry enzymatic assay for six lysosomal storage disorders (LSDs) including Pompe disease, Fabry disease, Gaucher disease, mucopolysaccharidosis type I (MPS-I), Niemann-Pick type A/B, and Krabbe disease. Screen-positive cases were confirmed using leukocyte enzymatic activity and DNA molecular analysis.

RESULTS

From July 2012 to April 2016, 20,018 patients were screened; 20 patients were confirmed to have an LSD phenotype (99.9 in 100,000 newborns). Final distributions include 11 Pompe disease, five Fabry disease, two MPS-I, and two Niemann-Pick type A/B patients. We did not find any Gaucher or Krabbe patients. A final frequency of 1 in 1001 LSD newborn phenotypes was established.

DISCUSSION

NBS is a major public health achievement that has decreased the morbidity and mortality of inborn errors of metabolism. The introduction of NBS for LSD presents new challenges. This is the first multiplex Latin-American study of six LSDs detected through NBS.

Identification of a Novel GLA Mutation (L206 P) in a Patient with Fabry Disease

We report a new α-Galactosidase A (αGal-A) mutation in a 39-year-old Korean born, male Fabry disease patient. Fabry disease is a devastating, progressive inborn error of metabolism caused by X-linked genetic mutations. In this case, the first clinical symptom to occur was in childhood consisting of a burning pain originating in the extremities then radiating inwards to the limbs. This patient also stated to have ringing in his ears, angiokeratomas on his trunk, and cornea verticillata. He visited an outpatient cardiologist due to intermittent and atypical chest discomfort at the age of 39. Electrocardiographic and echocardiographic examination showed left ventricular hypertrophy. A physical examination revealed proteinuria without hematuria. The patient's plasma αGal-A activity was markedly lower than the mean value of the controls. After genetic counseling and obtaining written informed consent, we identified one hemizygous mutation in exon 4 of galactosidase alpha, c.617T>C (p.Leu206 Pro). He was eventually diagnosed as having Fabry disease.

The Impact of Fabry Disease on Reproductive Fitness

Fabry disease (FD) is a pan-ethnic, X-linked, progressive lysosomal storage disorder caused by pathogenic mutations in the GLA gene. Published case reports and abstracts suggest that decreased reproductive fitness may occur in males with FD. In order to understand the impact of FD on reproductive fitness and increase the accuracy of reproductive genetic counseling, this study examines a large, multi-centered population of individuals with FD to determine if males have reduced reproductive fitness. Study data were collected on 376 patients through two, gender-specific surveys distributed across the United States and Canada. The number of biological live-born children among individuals with FD was compared to statistics from the general population. Information was also collected on reduced sperm count, depression, pain, use of assisted reproductive technology, and reproductive choice. On average, females affected by FD had more biological live-born children (1.8) than males affected by FD (1.1). However, males affected by FD had an increased mean number of biological children (1.1) compared to the mean number of biological children fathered by men in the United States (0.9). Sixteen of the 134 males with FD reported oligospermia, which suggests that an infertility work up may be indicated for males having difficulty impregnating their partners. In our large multicenter sample, males and females with FD do not exhibit reduced reproductive fitness; on average they have more biological children than the general population in the United States. This information should assist clinicians in providing accurate reproductive genetic counseling and treatment for individuals with FD.

A new mutation found in newborn screening for Fabry disease evaluated by plasma globotriaosylsphingosine levels

A pilot study of newborn screening for Fabry disease was performed in Okinawa, Japan. A total of 2,443 neonates were screened using dried blood spot samples over 7 years starting in 2007. Of 13 neonates determined to have low α-galactosidase A (GLA) activity, one boy had a new missense mutation, p.G144D of the GLA gene. This mutation was considered to be a late-onset type, as evaluated based on plasma globotriaosylsphingosine levels and family history.

Fabry disease in children: a federal screening programme in Russia

Our objective was to examine the prevalence of Fabry disease in Russian children with chronic pain in the distal limbs. This non-interventional, multi-centre study included children 2-18 years of age with chronic recurrent unilateral or bilateral pain, burning, or acroparesthesia in the hands or feet. The presence of Fabry disease was defined by abnormal alpha-galactosidase A activity in males or alpha-galactosidase gene (GLA) mutation in females. Among 214 patients (110 males), 84.1% had bilateral limb pain and 31.8% had unilateral limb pain recorded at some time point; 61 (28.5%) patients had a positive family history possibly associated with Fabry disease. Alpha-galactosidase A activity was within the normal range in all 109 of the male patients tested. One female patient had a GLA mutation (C937G > T) and alpha-galactosidase A activity within the normal range.

CONCLUSION

We did not find definitive evidence of Fabry disease in these children with a history of chronic recurrent unilateral or bilateral limb pain or acroparesthesia. The presence of chronic limb pain does not appear to be highly predictive of a diagnosis of Fabry disease in Russian children and adolescents, suggesting that key early signs and symptoms of Fabry disease are not specific to the disease. What is Known: • Signs and symptoms of Fabry disease are seen in children < 10 years of age; pain in the distal limbs is a common early symptom. What is New: • Fabry disease was not diagnosed in this population of Russian children with a history of chronic limb pain. • The presence of acroparesthesia or chronic limb pain does not appear to be highly predictive of a diagnosis of Fabry disease in Russian children and adolescents, suggesting that these early symptoms of Fabry disease are not specific to the disease.

Newborn screening for Fabry disease in the north-west of Spain

Fabry disease is an X-linked lysosomal storage disorder caused by the impairment of α-galactosidase A. Enzyme replacement therapy is available to treat patients, who often experience delayed diagnosis. A newborn screening for Fabry disease was performed to study the prevalence of the pathology and to evaluate the possibility to implement the test in systematic screenings. We collected 14,600 dried blood spot samples (7575 males and 7025 females) and carried out a diagnostic study by fluorometric measurement of α-galactosidase A enzymatic activity and GLA gene sequencing. We detected one patient with a mutation in GLA associated with classical Fabry Disease (M290I), ten subjects carrying genetic variants of uncertain diagnosis (S126G, R118C, A143T), and a girl with the non-characterized variant F18Y, which was not previously described. Additional 25 samples presented nucleotide substitutions described as polymorphisms (D313Y, rs2071225, and rs2071397). The estimated prevalence for Fabry disease in north-western Spanish males is of 0.013%.

CONCLUSION

These results confirm that the prevalence of Fabry disease is underestimated and systematic screening is feasible; however, further characterization of variants of uncertain clinical significance is necessary to establish protocols of patients' management. What is Known: • Fabry disease is a rare disease of delayed diagnosis, whose prevalence is underestimated. However, early diagnosis is important for better efficiency of the current available treatment. What is New: • This newborn screening for Fabry disease performed on Spanish population reveals a prevalence of genetic alterations in GLA of 0.1% in males (0.013% with classic Fabry disease) and also characterizes these modifications in order to discriminate between pathogenic mutations and genetic variants of unknown significance.

Newborn Screening for Lysosomal Storage Disorders

Newborn screening is one of the most important public health initiatives to date, focusing on the identification of presymptomatic newborn infants with treatable conditions to reduce morbidity and mortality. The number of screening conditions continues to expand due to advances in screening technologies and the development of novel therapies. Consequently, some of the lysosomal storage disorders are now considered as candidates for newborn screening, although many challenges including identification of late-onset phenotypes remain. This review provides a critical appraisal of the current state of newborn screening for lysosomal storage disorders.

Fabry Disease: A Disorder of Childhood Onset

BACKGROUND

Fabry disease, an X-linked disorder of glycosphingolipids, markedly increases the risk of systemic vasculopathy, ischemic stroke, small-fiber peripheral neuropathy, cardiac dysfunction, and chronic kidney disease.

METHODS

We performed an extensive PubMed search on the topic of Fabry disease and drew from our cumulative 43 years of experience.

RESULTS

Most of these complications are nonspecific in nature and clinically indistinguishable from similar abnormalities that occur in the context of more common disorders in the general population. This disease is caused by variants of the GLA gene, and its incidence may have been underestimated. However, one must also guard against overdiagnosis of Fabry disease and unjustified enzyme replacement therapy, because some of the gene variants are benign. Specific therapy for Fabry disease has been developed in the last few years, but its clinical effect has been modest. Novel therapeutic agents are being developed. Standard "nonspecific" medical and surgical therapy is necessary and effective in slowing deterioration or compensating for organ failure in patients with Fabry disease.

CONCLUSIONS

Fabry disease is a treatable and modifiable genetic risk factor for a myriad of clinical organ complications. Fabry disease may be frequently overlooked but on occasion overdiagnosed.

Screening of Fabry disease in patients with end-stage renal disease of unknown etiology: the first Thailand study

We aimed to explore the prevalence of Fabry disease in Thai patients who were diagnosed with end-stage renal disease (ESRD) of an unknown origin. Venous blood samples were collected from ESRD patients for biochemical and molecular studies. Alpha-galactosidase A (α-GAL A) screening was performed from dried-blood spots using fluorometry. Molecular confirmation was performed using DNA sequencing of the GLA gene. A total of 142 male and female patients were included in this study. Ten patients (7.04%) exhibited a significant decrease in α-GAL A activity. There were no definitive pathogenic mutations observed in the molecular study. However, four patients revealed a novel nucleotide variant at c.1 -10 C>T, which was identified as a benign variant following screening in the normal population. In conclusion, the α-GAL A assay utilizing dried-blood spots revealed a significant false positive rate. There was no definitive Fabry disease confirmed in Thai patients diagnosed with ESRD of unknown etiology.

Experiences of Being Heterozygous for Fabry Disease: a Qualitative Study

Little is known about the experiences of women with Fabry disease. The aim of this study was to explore women's experiences of being heterozygous for Fabry disease. We used an explorative qualitative study design and selected ten Norwegian women who were known heterozygous for Fabry disease to participate. We conducted in-depth semi-structured interviews and analyzed the interviews using inductive thematic analysis. We found that learning about one's heterozygous status may be devastating for some. However, for most of the participants, heterozygous status, as well as doctors' acceptance of symptoms in women heterozygous for Fabry disease, provided an explanation and relief. Although many women did not consider themselves ill, they wished to be acknowledged as more than "just carriers." The participants were grateful for enzyme replacement therapy, although it had its burdens regarding time, planning, and absences from school or work. Women with Fabry disease felt that the lack of knowledge among healthcare professionals about Fabry disease was frustrating and worrisome. These findings suggest that healthcare professionals should acknowledge the different ways women react to their diagnosis, and be aware of the personal costs of receiving treatment.

Expanded newborn screening by mass spectrometry: New tests, future perspectives

Tandem mass spectrometry (MS/MS) has become a leading technology used in clinical chemistry and has shown to be particularly sensitive and specific when used in newborn screening (NBS) tests. The success of tandem mass spectrometry is due to important advances in hardware, software and clinical applications during the last 25 years. MS/MS permits a very rapid measurement of many metabolites in different biological specimens by using filter paper spots or directly on biological fluids. Its use in NBS give us the chance to identify possible treatable metabolic disorders even when asymptomatic and the benefits gained by this type of screening is now recognized worldwide. Today the use of MS/MS for second-tier tests and confirmatory testing is promising especially in the early detection of new disorders such as some lysosomal storage disorders, ADA and PNP SCIDs, X-adrenoleucodistrophy (X-ALD), Wilson disease, guanidinoacetate methyltransferase deficiency (GAMT), and Duchenne muscular dystrophy. The new challenge for the future will be reducing the false positive rate by using second-tier tests, avoiding false negative results by using new specific biomarkers and introducing new treatable disorders in NBS programs.

Anderson-Fabry cardiomyopathy: prevalence, pathophysiology, diagnosis and treatment

Anderson-Fabry disease (AFD) is a lysosomal storage disease caused by the inappropriate accumulation of globotriaosylceramide in tissues due to a deficiency in the enzyme α-galactosidase A (α-Gal A). Anderson-Fabry cardiomyopathy is characterized by structural, valvular, vascular and conduction abnormalities, and is now the most common cause of mortality in patients with AFD. Large-scale metabolic and genetic screening studies have revealed AFD to be prevalent in populations of diverse ethnic origins, and the variant form of AFD represents an unrecognized health burden. Anderson-Fabry disease is an X-linked disorder, and genetic testing is critical for the diagnosis of AFD in women. Echocardiography with strain imaging and cardiac magnetic resonance imaging using late enhancement and T1 mapping are important imaging tools. The current therapy for AFD is enzyme replacement therapy (ERT), which can reverse or prevent AFD progression, while gene therapy and the use of molecular chaperones represent promising novel therapies for AFD. Anderson-Fabry cardiomyopathy is an important and potentially reversible cause of heart failure that involves LVH, increased susceptibility to arrhythmias and valvular regurgitation. Genetic testing and cardiac MRI are important diagnostic tools, and AFD cardiomyopathy is treatable if ERT is introduced early.

Identification of a novel GLA mutation (F69 L) in a Japanese patient with late-onset Fabry disease

Fabry disease is an X-linked recessive inborn error of glycosphingolipid catabolism caused by a mutation in the GLA gene. We sequenced the α-galactosidase A gene (GLA) of a patient who had been clinically diagnosed with late-onset Fabry disease. Abundant globotriaosylceramide was present in his urine, which indicated typical Fabry disease. Here, we report a novel hemizygous mutation, c.207C>A (Phe69 Leu), which caused a mild/late-onset form of Fabry disease.

Prevalence of Fabry disease in dialysis patients: Japan Fabry disease screening study (J-FAST)

BACKGROUND

In Fabry disease, progressive glycolipid accumulation leads to damage in kidney and other organs. This study was designed to determine the prevalence rate of Fabry disease in Japanese dialysis patients.

METHODS

All dialysis patients agreeing to Japan Fabry disease screening study (J-FAST) with informed consent were selected except for Fabry disease. The screening was performed by a method of measuring plasma and/or leukocytes lysosomal α-galactosidase A protein level and α-galactosidase A activity. If positive, genetic analysis was carried out upon patient's agreement.

RESULTS

J-FAST dealt with 8547 patients (male 5408, female 3139). At the tertiary examination, 26 out of 8547 patients were found to be positive. Six out of 26 patients could not accept genetic analysis because of death. Remaining 20 patients agreed with genetic analysis; then 2 patients (male 2, female 0) had a variation of the α-Gal gene and 11 patients showed E66Q variations. Therefore, the frequency of Fabry disease in J-FAST was 0.04 % (2/5408) in males and 0 % (0/3139) in females, and then 0.02 % (2/8547) in all patients. The presumptive clinical diagnoses of end-stage kidney disease (ESKD) were 10 chronic glomerulonephritis, 7 diabetic nephropathy, 3 unknown etiology, 3 nephrosclerosis, 1 gouty nephropathy, 1 autosomal dominant polycystic kidney disease and 1 renal tuberculosis among 26 tertiary positive patients. Two male Fabry patients were initially diagnosed as nephrosclerosis and chronic glomerulonephritis.

CONCLUSIONS

The prevalence rate of Fabry disease in J-FAST was 0.02 %. Moreover, Fabry disease could not be ruled out as the clinical diagnosis of ESKD.

Clinical and biochemical investigation of male patients exhibiting membranous cytoplasmic bodies in biopsied kidney tissues; a pitfall in diagnosis of Fabry disease

Background: The existence of membranous cytoplasmic bodies in biopsied kidney tissues is one of the important findings when considering Fabry disease as the first choice diagnosis. However, there are possible acquired lysosomal diseases associated with pharmacological toxicity, although less attention has been paid to them.

Case Presentation: We experienced 3 male patients presenting with proteinuria and specific pathological changes strongly suggesting Fabry disease. We sought detailed clinical and biochemical information to avoid a wrong diagnosis. The patients were examined clinically and pathologically, and plasma α-galactosidase A (GLA) activity and the globotriaosylsphingosine (lyso-Gb3) concentrations were measured. Electron microscopic examination revealed numerous membranous inclusion bodies in podocytes, and biochemical analysis revealed normal GLA activity and a normal lyso-Gb3 level in plasma, showing that they did not have Fabry disease. They suffered from hyperlipidemia, myeloma, or lupus nephritis. They had received pitavastatin calcium, clarithromycin, loxoprofen and/or prednisolone, and there was no medication history of cationic amphiphilic drugs.

Conclusions: In this case series, the etiology of the inclusions was not clarified. However, these cases indicate that careful attention should be paid on diagnosis of patients exhibiting inclusion bodies in kidney cells, and it is important to confirm their past and present illnesses, and medication history as well as to measure the GLA activity and lyso-Gb3 level.

Late onset variants in Fabry disease: Results in high risk population screenings in Argentina

Background

Screening for Fabry disease (FD) in high risk populations yields a significant number of individuals with novel, ultra rare genetic variants in the GLA gene, largely without classic manifestations of FD. These variants often have significant residual α-galactosidase A activity. The establishment of the pathogenic character of previously unknown or rare variants is challenging but necessary to guide therapeutic decisions.

Objectives

To present 2 cases of non-classical presentations of FD with renal involvement as well as to discuss the importance of high risk population screenings for FD.

Results

Our patients with non-classical variants were diagnosed through FD screenings in dialysis units. However, organ damage was not limited to kidneys, since LVH, vertebrobasilar dolichoectasia and cornea verticillata were also present. Lyso-Gb3 concentrations in plasma were in the pathologic range, compatible with late onset FD. Structural studies and in silico analysis of p.(Cys174Gly) and p.(Arg363His), employing different tools, suggest that enzyme destabilization and possibly aggregation could play a role in organ damage.

Conclusions

Screening programs for FD in high risk populations are important as FD is a treatable multisystemic disease which is frequently overlooked in patients who present without classical manifestations.

Newborn screening for lysosomal storage disorders

Every newborn in the U.S. is screened for at least 29 disorders, where evidence suggests that early detection is possible and beneficial. With new or improved treatment options and development of high-throughput screening tests, additional conditions have been proposed for inclusion in newborn screening programs. Among those are several lysosomal storage disorders that have been evaluated in limited pilot studies or that are already included in a few national or international newborn screening programs. These conditions include Pompe disease, Niemann-Pick type A/B disease, Fabry disease, Krabbe disease, Mucopolysaccharidoses types I and II, and Gaucher disease. Here, we review the current state of newborn screening for these lysosomal storage disorders.

Current status of newborn screening worldwide: 2015

Newborn screening describes various tests that can occur during the first few hours or days of a newborn's life and have the potential for preventing severe health problems, including death. Newborn screening has evolved from a simple blood or urine screening test to a more comprehensive and complex screening system capable of detecting over 50 different conditions. While a number of papers have described various newborn screening activities around the world, including a series of papers in 2007, a comprehensive review of ongoing activities since that time has not been published. In this report, we divide the world into 5 regions (North America, Europe, Middle East and North Africa, Latin America, and Asia Pacific), assessing the current NBS situation in each region and reviewing activities that have taken place in recent years. We have also provided an extensive reference listing and summary of NBS and health data in tabular form.

Epidemiology and diagnosis of lysosomal storage disorders; challenges of screening

The lysosomal storage disorders (LSDs) are a group of genetic disorders resulting from defective lysosomal metabolism and subsequent accumulation of substrates. Patients present with a large phenotypic spectrum of disease manifestations that are generally not specific for LSDs, leading to considerable diagnostic delay and missed cases. Introduction of new disease modifying therapies for LSDs has made early diagnosis a priority. Increased awareness, but particularly the introduction of screening programs allow for early diagnosis and timely initiation of treatment. This review will provide insight into the epidemiology and diagnostic process for LSDs. In addition, challenges for carrier screening, high-risk screening and newborn population screening for LSDs are discussed.

Differential diagnosis of Mendelian and mitochondrial disorders in patients with suspected multiple sclerosis

Several single gene disorders share clinical and radiologic characteristics with multiple sclerosis and have the potential to be overlooked in the differential diagnostic evaluation of both adult and paediatric patients with multiple sclerosis. This group includes lysosomal storage disorders, various mitochondrial diseases, other neurometabolic disorders, and several other miscellaneous disorders. Recognition of a single-gene disorder as causal for a patient's 'multiple sclerosis-like' phenotype is critically important for accurate direction of patient management, and evokes broader genetic counselling implications for affected families. Here we review single gene disorders that have the potential to mimic multiple sclerosis, provide an overview of clinical and investigational characteristics of each disorder, and present guidelines for when clinicians should suspect an underlying heritable disorder that requires diagnostic confirmation in a patient with a definite or probable diagnosis of multiple sclerosis.

Gender-specific plasma proteomic biomarkers in patients with Anderson-Fabry disease

AIMS

Anderson-Fabry disease (AFD) is an important X-linked metabolic disease resulting in progressive end-organ involvement, with cardiac disease being the dominant determinant of survival in a gender-dependent manner. Recent epidemiological screening for AFD suggests the prevalence is much higher than previously recognized, with estimates of 1:3000. Our aim was to discover novel plasma biomarker signatures in adult patients with AFD.

METHODS AND RESULTS

We used an unbiased proteomic screening approach to discover novel plasma biomarker signatures. In the discovery cohort of 46 subjects, 14 healthy controls and 32 patients with AFD, we used a mass spectrometry iTRAQ proteomic approach followed by multiple reaction monitoring (MRM) assays to identify biomarkers. Of the 38 protein groups discovered by iTRAQ, 18 already had existing MRM assays. Based on MRM, we identified an eight-protein biomarker panel (22 kDa protein, afamin, α1 antichymotrypsin, apolipoprotein E, β-Ala His dipeptidase, haemoglobin α-2, isoform 1 of sex hormone-binding globulin, and peroxiredoxin 2) that was very specific and sensitive for male AFD patients. In female AFD patients, we identified a nine-marker panel of proteins with only three proteins, apolipoprotein E, haemoglobin α-2, and peroxiredoxin 2, common to both genders, suggesting a gender-specific alteration in plasma biomarkers in patients with AFD. The biomarkers were validated in plasma samples from 48 subjects using MRM, and they performed inferiorly in patients with heart failure.

CONCLUSIONS

We have identified gender-specific plasma protein biomarker panels that are specific and sensitive for the AFD phenotype. The gender-specific panels offer important insight into potential differences in pathophysiology and prognosis between males and females with AFD.

Lysosomal storage disorder screening implementation: findings from the first six months of full population pilot testing in Missouri

OBJECTIVE

To evaluate the performance of a statewide full-population pilot study in Missouri on newborn blood spots for screening of lysosomal storage disorders (LSDs) using digital microfluidics.

STUDY DESIGN

A full-population pilot study using a multiplexed fluorometric enzymatic assay to detect Pompe disease, Fabry disease, Gaucher disease, and mucopolysaccharidosis type I (MPS I) in the Missouri newborn population is ongoing. Provisional cutoff values were determined during a prepilot study. All newborn dried blood spots received at the Missouri State Public Health Laboratory for routine newborn screening were screened for the 4 LSDs during the pilot study. Newborns determined to be screen-positive were referred for confirmatory testing.

RESULTS

The study commenced on January 11, 2013; during the first 6 months, 43,701 specimens were screened, and 27 newborns with a confirmed diagnosis of an LSD genotype (8 with Pompe disease, 1 with Gaucher disease, 15 with Fabry disease, and 3 with MPS I) were identified. These numbers correspond to detection rates of 1:5463 for Pompe disease, 1:43,701 for Gaucher disease, 1:2913 for Fabry disease, and 1:14,567 for MPS I. The positive predictive values were 47% for Pompe disease with 1 lost to follow-up, 10% for Gaucher disease, 58% for Fabry disease with 2 lost to follow-up, and 11% for MPS I with 4 pending.

CONCLUSION

The first 6 months of the Missouri LSD pilot study provided the opportunity to validate the effectiveness of the digital microfluidic screening method, refine the cutoffs for detection of these LSDs, and test the entire system of infant referral, follow-up, confirmation, treatment, and screening program communication.

Fabry disease in infancy and early childhood: a systematic literature review

PURPOSE

Fabry disease is a pan-ethnic, progressive, X-linked genetic disorder that commonly presents in childhood and is caused by deficient activity of the lysosomal enzyme alpha-galactosidaseA (α-gal A). Symptoms of Fabry disease in the pediatric population are well described for patients over five years of age; however, data are limited for infancy and early childhood. The purpose of this article is to delineate the age of detection for specific Fabry symptoms in early childhood.

METHODS

A systematic retrospective analysis of PubMed indexed, peer-reviewed publications and case reports in the pediatric Fabry population was performed to review symptoms in patients reported before 5 years of age.

RESULTS

The most frequently reported symptom in all age groups under 5 years was acroparesthesias/neuropathic pain, reported in 9 children, ranging in age from 2.0-4.0 years. Also notable is the frequency of gastrointestinal issues reported in 6 children aged 1.0-4.1 years of age.

CONCLUSION

This article finds clear evidence that symptoms can occur in early childhood, before age 5 years. Given early presenting symptoms and the ability to monitor these disease hallmarks, a timely referral to a medical geneticist or other specialty clinician experienced in managing children with Fabry disease is strongly indicated.

Frequency of de novo mutations in Japanese patients with Fabry disease

We examined alpha-galactosidase A (GLA) gene mutations in 74 Japanese families with Fabry disease (FD) to determine the frequency of de novo mutations. In 5 of 74 families (6.8%), the probands had no positive family histories and were diagnosed as de novo because their parents had no mutations in GLA gene. The parents of Fabry patients do not necessarily have mutations in GLA gene which is an important consideration in genetic counseling for FD.

Endomyocardial biopsies in patients with left ventricular hypertrophy and a common Chinese later-onset Fabry mutation (IVS4 + 919G > A)

BACKGROUND

In Taiwan, DNA-based newborn screening showed a surprisingly high incidence of a cardiac Fabry mutation (IVS4 + 919G > A). The prevalence of this mutation is too high to be believed that it is a real pathogenic mutation. The purpose of this study is to identify the cardiac pathologic characteristics in patients with left ventricular hypertrophy and this mutation

METHODS AND RESULTS

Endomyocardial biopsies were obtained in 22 patients (Median age: 61, males: 17; females: 5) with left ventricular hypertrophy and the IVS4 + 919G > A mutation; five patients had not received enzyme replacement therapy (ERT) before biopsy, while the other 17 patients had received ERT from 8 months to 51 months. Except for three patients who had received ERT for more than 3 years, all other patients showed significant pathological change and globotriaosylceramide (Gb3) accumulation in their cardiomyocytes. In contrast to classical Fabry patients, no Gb3 accumulation was found in the capillary endothelial cells of any of our patients. Fourteen patients (63.6%) were found to have myofibrillolysis.

CONCLUSIONS

All of the untreated and most of the treated IVS4 + 919G > A patients showed typical pathological changes of Fabry disease in their cardiomyocytes. No endothelial accumulation of Gb3 was found, which is similar to the findings of several previous reports regarding later-onset Fabry disease. This result highly suggests that the IVS4 + 919G > A is a real pathogenic later-onset Fabry mutation.