Heterogeneity of disease-causing variants in the Swedish galactosemia population: Identification of 16 novel GALT variants

The aim was to determine disease-causing variants in the GALT gene which codes for the enzyme galactose-1-phosphate uridylyltransferase. Loss of activity of this enzyme causes classical galactosemia-a life threatening, treatable disorder, included in the Swedish newborn screening program since 1967. A total of 66 patients with the disease are known in Sweden and 56 index patients were investigated. An additional two patients with Duarte galactosemia were included. The disease-causing variants were identified in all patients. As reported from other countries only a few variants frequently recur in severe disease. The two variants p.(Gln188Arg) (c.563A\u3eG) and p.(Met142Lys) (c.425T\u3eA) are present in several index patients whereas the remaining are found in one to three patients each. The most common variant, p.(Gln188Arg), has an allele frequency of 51% in the cohort. A total of 16 novel variants were found among the 33 different variants in the cohort. Two of these are synonymous variants affecting splicing, demonstrating the importance of the evaluation of synonymous variants at the cDNA level. Concise sentence: Galactosemia is a rare disease in Sweden and the disease-causing variants are heterogenous including two synonymous variants

Screening for C3 Deficiency in Newborns Using Microarrays

BACKGROUND: Dried blood spot samples (DBSS) from newborns are widely used in neonatal screening for selected metabolic diseases and diagnostic possibilities for additional disorders are continuously being evaluated. Primary immunodeficiency disorders comprise a group of more than one hundred diseases, several of which are fatal early in life. Yet, a majority of the patients are not diagnosed due to lack of high-throughput screening methods. METHODOLOGY/PRINCIPAL FINDINGS: We have previously developed a system using reverse phase protein microarrays for analysis of IgA levels in serum samples. In this study, we extended the applicability of the method to include determination of complement component C3 levels in eluates from DBSS collected at birth. Normal levels of C3 were readily detected in 269 DBSS from healthy newborns, while no C3 was detected in sera and DBSS from C3 deficient patients. CONCLUSIONS/SIGNIFICANCE: The findings suggest that patients with deficiencies of specific serum proteins can be identified by analysis of DBSS using reverse phase protein microarrays.QC 20120213</p

Newborn screening for presymptomatic diagnosis of complement and phagocyte deficiencies

The clinical outcomes of primary immunodeficiencies (PIDs) are greatly improved by accurate diagnosis early in life. However, it is not common to consider PIDs before the manifestation of severe clinical symptoms. Including PIDs in the nation-wide newborn screening programs will potentially improve survival and provide better disease management and preventive care in PID patients. This calls for the detection of disease biomarkers in blood and the use of dried blood spot samples, which is a part of routine newborn screening programs worldwide. Here, we developed a newborn screening method based on multiplex protein profiling for parallel diagnosis of 22 innate immunodeficiencies affecting the complement system and respiratory burst function in phagocytosis. The proposed method uses a small fraction of eluted blood from dried blood spots and is applicable for population-scale performance. The diagnosis method is validated through a retrospective screening of immunodeficient patient samples. This diagnostic approach can pave the way for an earlier, more comprehensive and accurate diagnosis of complement and phagocytic disorders, which ultimately lead to a healthy and active life for the PID patientsThis work was supported by the Swedish Research Council (VR) and grants provided by the Stockholm County Council (ALF)

Gunnar Jungner and the Principles and Practice of Screening for Disease

We present a biography of Gunnar Jungner, one of the authors of the Principles and Practice of Screening for Disease by JMG Wilson and G Jungner, published by the WHO in 1968. This publication contains ten criteria, which are still consulted, when a new disorder is evaluated for inclusion in a screening program. Gunnar Jungner was a Swedish MD, PhD, specialized in Clinical Chemistry, born in Sweden in 1914. In 1961 he built an automated instrument for the analysis of different components in plasma, with the aim to detect diseases in presumably healthy individuals, to enable start of treatment at an early disease stage. This first automated instrument for Clinical Chemistry in Sweden was used in a screening project, where 90 000 seemingly healthy individuals were included. The study was discussed extensively and he was invited to present the results at different international meetings, where he also met JMG Wilson. Gunnar Jungner developed the instrument further together with his brother Ingmar and the Swedish gas company AGA. The brothers also established an out-patient ward in Stockholm, where people could come for health screening

Incidence of Glucose-6-Phosphate Dehydrogenase Deficiency among Swedish Newborn Infants

Sweden has 10.2 million inhabitants and more than 2.4 million have a foreign background. A substantial number of immigrants come from countries where glucose-6-phosphate dehydrogenase deficiency (G6PDD) is frequent. The total birth rate annually in Sweden is approximately 117,000 and newborn screening is centralized to one laboratory. We determined glucose-6-phosphate dehydrogenase (G6PD) activity in 10,098 dried blood spot samples (DBS) from the whole country with a fluorometric assay (LabSystems Diagnostics Oy, Finland). The first 5451 samples were anonymised and run as singletons, whilst the following 4647 samples were coded. Enzyme activity &le;40% of the mean of the day was found in 58 samples (1/170) and among these, 29 had activities &le;10% (1/350). Twenty-nine samples with residual activities between 2&ndash;39% in the coded cohort were subjected to Sanger sequencing. Disease-causing variants were identified in 26 out of 29 infants, of which six were girls. In three patients, we did not find any disease-causing variants, although two patients were hemizygous for the known polymorphisms c.1311T&gt;C and c.1365-13C&gt;T. The most common disease-causing variant found in 15 of the 29 samples (12 hemizygotes, two heterozygotes, one homozygote) was the Mediterranean mutation, c.563C&gt;T (p.(Ser188Phe)) in exon 6. G6PDD is thus a surprisingly prevalent disorder in Sweden

<i>MCEE</i> Mutations in an Adult Patient with Parkinson’s Disease, Dementia, Stroke and Elevated Levels of Methylmalonic Acid

Methylmalonic aciduria (MMA-uria) is seen in several inborn errors of metabolism (IEM) affecting intracellular cobalamin pathways. Methylmalonyl-CoA epimerase (MCE) is an enzyme involved in the mitochondrial cobalamin-dependent pathway generating succinyl-CoA. Homozygous mutations in the corresponding MCEE gene have been shown in children to cause MCE deficiency with isolated MMA-uria and a variable clinical phenotype. We describe a 78-year-old man with Parkinson&#8217;s disease, dementia and stroke in whom elevated serum levels of methylmalonic acid had been evident for many years. Metabolic work-up revealed intermittent MMA-uria and increased plasma levels of propionyl-carnitine not responsive to treatment with high-dose hydroxycobalamin. Whole genome sequencing was performed, with data analysis targeted towards genes known to cause IEM. Compound heterozygous mutations were identified in the MCEE gene, c.139C&gt;T (p.Arg47X) and c.419delA (p.Lys140fs), of which the latter is novel. To our knowledge, this is the first report of an adult patient with MCEE mutations and MMA-uria, thus adding novel data to the possible phenotypical spectrum of MCE deficiency. Although clinical implications are uncertain, it can be speculated whether intermittent hyperammonemia during episodes of metabolic stress could have precipitated the patient&#8217;s ongoing neurodegeneration attributed to Parkinson&#8217;s disease

Newborn Screening for Primary Immune Deficiencies with a TREC/KREC/ACTB Triplex Assay—A Three-Year Pilot Study in Sweden

Background: Screening newborns for severe combined immunodeficiency (SCID) has become essential, since efficient methods to identify infants with these disorders exist and early stem cell transplantation is life-saving. Method: We performed a three-year screening trial in Stockholm comprised of 89,462 newborn infants. The number of T-cell receptor excision circle (TREC)/kappa-deleting recombination excision circle (KREC)/β-actin (ACTB) copies were quantified simultaneously by real time polymerase chain reaction (PCR) in 3.2 mm punches from dried blood samples taken in the regular neonatal screening program. Results: Five patients with immune deficiencies were identified: two with SCID caused by mutations in the Artemis- and adenosine deaminase gene, respectively, one with ataxia telangiectasia and two with reversible agammagloblinemia, which so far, is of unknown cause. This points to an incidence of SCID at the same level as in other studies (around 1:50,000). In 19 recalled infants, low KREC levels and in one case, also low TREC levels, were caused by immunosuppressive treatment of the mother during pregnancy. The levels normalized within a month in all these infants. The total recall rate was 0.10%, and 40% of the recalled infants were born prematurely (&lt;37 weeks gestation). Among 69 patients with inborn errors of metabolism screened retrospectively, only two, who were severely ill with organic acidemias when the sample was taken, and two with mitochondrial disorders, screened positive

Company "VU SANTEHNIKA" marketing environment analysis and development opportunities

There is a need for neonatal screening tools to improve the long-term clinical outcome of patients with primary immunodeficiency diseases (PID). Recently, a PCR-based screening method for both TRECs and KRECs using Guthrie card samples has been developed. However, the applicability of these excision circle assays is limited to patients with severe T or B cell lymphopenia (SCID, XLA and A-T), whereas the most common forms of PID are not detected. Absence of serum IgA is seen in a major fraction of patients with immunological defects. As serum IgA in newborns is considered to be of fetal origin, eluates from routinely collected dried blood spot samples might thus be suitable for identification of children with PID. To assess the applicability of such screening assays, stored Guthrie card samples were obtained from 47 patients with various forms of primary immunodeficiency diseases (SCID, XLA, A-T, HIGM and IgAD), 20 individuals with normal serum IgA levels born to IgA-deficient mothers and 51 matched healthy newborns. Surprisingly, normal serum IgA levels were found in all SCID, XLA, A-T and HIGM patients and, additionally, in all those IgAD patients born to IgA-sufficient mothers. Conversely, no serum IgA was found in any of the 16 IgAD patients born by IgA-deficient mothers. Moreover, half of the IgA-sufficient individuals born by IgA-deficient mothers also lacked IgA at birth whereas no IgA-deficient individuals were found among the controls. IgA in neonatal dried blood samples thus appears to be of both maternal and fetal origin and precludes its use as a reliable marker for neonatal screening of primary immunodeficiency diseases

Heat differentiated complement factor profiling.

Complement components and their cascade of reactions are important defense mechanisms within both innate and adaptive immunity. Many complement deficient patients still remain undiagnosed because of a lack of high throughput screening tools. Aiming towards neonatal proteome screening for immunodeficiencies, we used a multiplex profiling approach with antibody bead arrays to measure 9 complement proteins in serum and dried blood spots. Several complement components have been described as heat sensitive, thus their heat-dependent detectability was investigated. Using sera from 16 patients with complement deficiencies and 23 controls, we confirmed that the proteins C1q, C2, C3, C6, C9 and factor H were positively affected by heating, thus the identification of deficient patients was improved when preheating samples. Measurements of C7, C8 and factor I were negatively affected by heating and non-heated samples should be used in analysis of these components. In addition, a proof of concept study demonstrated the feasibility of labeling eluates from dried blood spots to perform a subsequent correct classification of C2-deficiencies. Our study demonstrates the potential of using multiplexed single binder assays for screening of complement components that open possibilities to expand such analysis to other forms of deficiencies