Progressive nephropathy is one of the main features of Fabry disease, which largely contributes to the overall morbidity and mortality burden of the disease. Due to the lack of specific biomarkers, ...the heterogeneity of the disease, and unspecific symptoms, diagnosis is often delayed. Clinical presentation in individual patients varies widely, even in patients from the same family carrying the same pathogenic
variant. Therefore, it is reasonable to anticipate that additional genomic, transcriptomic, proteomic, and metabolomics factors influence the manifestation and progression of the disease. The aim of this article is to provide an overview of nephropathy in Fabry patients and the biomarkers currently used in the diagnosis and follow-up. Current biomarkers are associated with late signs of kidney damage. Therefore, there is a need to identify biomarkers associated with early stages of kidney damage that would enable early diagnosis, which is crucial for effective treatment and prevention of severe irreversible complications. Recent advances in sequencing and -omics technologies have led to several studies investigating new biomarkers. We will provide an overview of the novel biomarkers, critically evaluate their clinical utility, and propose future perspectives, which we believe might be in their integration.
In the last decade, the development of high-throughput sequencing methodologies has significantly improved the gathering of genomic information and consequent under-standing of the genetic and ...epigenetic background of complex and monogenetic endocrine disorders ...
Telomeres are dynamic DNA nucleoprotein structures located at the end of chromosomes where they maintain genomic stability. Due to the end replication problem, telomeres shorten with each cell ...division. Critically short telomeres trigger cellular senescence, which contributes to various degenerative and age-related diseases, including chronic kidney diseases (CKDs). Additionally, other factors such as oxidative stress may also contribute to accelerated telomere shortening. Indeed, telomeres are highly susceptible to oxidative damage due to their high guanine content. Here, we provide a comprehensive review of studies examining telomere length (TL) in CKDs to highlight the association between TL and the development and progression of CKDs in humans. We then focus on studies investigating TL in patients receiving kidney replacement therapy. The mechanisms of the relationship between TL and CKD are not fully understood, but a shorter TL has been associated with decreased kidney function and the progression of nephropathy. Interestingly, telomere lengthening has been observed in some patients in longitudinal studies. Hemodialysis has been shown to accelerate telomere erosion, whereas the uremic milieu is not reversed even in kidney transplantation patients. Overall, this review aims to provide insights into the biological significance of telomere attrition in the pathophysiology of kidney disease, which may contribute to the development of new strategies for the management of patients with CKDs.
Lysosomal acid lipase deficiency (LAL-D) is an autosomal recessive lysosomal storage disorder, caused by homozygous or compound heterozygous pathogenic variants in the
LIPA
gene. Clinically, LAL-D is ...under- and misdiagnosed, due to similar clinical and laboratory findings with other cholesterol or liver misfunctions. As a part of the Slovenian universal familial hypercholesterolemia (FH) screening, LAL-D is screened as a secondary condition among other rare dyslipidemias manifesting with hypercholesterolemia. Out of 669 children included, three were positive for a homozygous disease-causing splicing variant NM_000235.4: c.894G > A (NP_000226.2:p. Gln298Gln) in the
LIPA
gene (NG_008194.1). The mean age by the diagnosis of LAL-D was 9.8 ± 0.9 years. Moreover, all three LAL-D-positive children had an important elevation of transaminases and decreased activity of the lysosomal acid lipase enzyme. Abdominal MRI in all children detected an enlarged liver but a normal-sized spleen. In conclusion, universal FH screening algorithms with the confirmatory genetic analysis in the pediatric population enable also rare dyslipidemia detection at an early age. An important clinical criterion for differentiation between FH and the LAL-D-positive children has elevated transaminase levels (AST and ALT). In all three LAL-D positive children, an improvement in cholesterol and transaminase levels and steatosis of the liver has been seen after early treatment initiation.
Contrary to many western European countries, most south-eastern European countries do not have an expanded newborn screening (NBS) program using tandem mass spectrometry. This study would represent ...one of the first expanded NBS studies in south-eastern Europe and will enable the estimation of the incidences of IEM in Slovenia. We proposed an expanded NBS approach including next-generation sequencing (NGS) as a confirmational analysis.
We conducted a pilot study of expanded NBS for selected inborn errors of metabolism (IEM) in Slovenia including 10,048 NBS cards. We used an approach including tandem mass spectrometry followed by second tier tests including NGS. Based on the NBS results, 85 children were evaluated at a metabolic follow-up; 80 of them were analyzed using NGS.
Altogether, glutaric acidemia type 1 was confirmed in one patient who was a compound heterozygote for two known causative GCDH variants. A patient with suspected very long-chain acyl-CoA dehydrogenase deficiency had negative metabolic follow-up tests, but had two heterozygous ACADVL variants; one known disease-causing variant and one indel, namely c.205-8_205-7delinsGC, that is predicted to be causative. Nine participants had elevated metabolites characteristic of 3-methylcrotonyl-CoA carboxylase deficiency, 2 of them had known causative homozygous variants in MCCC1. The other seven were heterozygous; two had a novel genetic variant c.149_151dupCCA (p.Thr50dup). Cumulative incidences of IEM in Slovenia were similar to other European countries.
NGS proved to be valuable in explaining the abnormal metabolite concentrations in NBS as it enabled the differentiation between affected patients and mere heterozygotes, and it improved the turnaround time of genetic analysis. The results of this study will be instrumental in the routine implementation of expanded NBS in Slovenia.
•Incidences of IEM in Slovenia are similar to other European countries.•NGS proved to be a valuable tool in explaining abnormal metabolite concentrations.•The implementation of NGS as a first follow-up would improve the NBS programmes.•Implementation of expanded NBS is recommended for Slovenia.
Abstract Background Individuals with familial hypercholesterolemia (FH) who are untreated have up to 100-fold elevated risk for cardiovascular complications compared with those who are unaffected. ...Data for identification of FH with a universal screening for hypercholesterolemia in children are lacking. Objectives This study sought genetic identification of FH from a cohort of children with elevated serum total cholesterol (TC) concentration, detected in a national universal screening for hypercholesterolemia. Methods Slovenian children born between 1989 and 2009 (n = 272) with TC >6 mmol/l (231.7 mg/dl) or >5 mmol/l (193.1 mg/dl) plus a family history positive for premature cardiovascular complications, identified in a national universal screening for hypercholesterolemia at 5 years of age were genotyped for variants in LDLR , PCSK9 , APOB , and APOE. Results Of the referred children, 57.0% carried disease-causing variants for FH: 38.6% in LDLR , 18.4% in APOB , and none in PCSK9 . Nine novel disease-causing variants were identified, 8 in LDLR , and 1 in APOB . Of the remaining participants, 43.6% carried the APOE E4 isoform. Estimated detection rate of FH in the universal screening program from 2009 to 2013 was 53.6% (95% confidence interval CI: 34.5% to 72.8%), peaking in 2013 with an upper estimated detection rate of 96.3%. Variants in LDLR , APOB , or the APOE E4 isoform occurred in 48.6%, 60.0%, and 76.5%, respectively, of patients with a family history negative for cardiovascular complications. Conclusions Most participants who were referred from a national database of universal screening results for hypercholesterolemia had genetically confirmed FH. Data for family history may not suffice for reliable identification of patients through selective and cascade screening.
In contrast to the recessive form, hearing loss inherited in a dominant manner is more often post-lingual and typically results in a progressive sensorineural hearing loss with variable severity and ...late onset. Variants in the
gene are an extremely rare cause of dominantly inherited hearing loss. Genetic testing is a crucial part of the identification of the etiology of hearing loss in individual patients, especially when performed with next-generation sequencing, enabling simultaneous analysis of numerous genes, including those rarely associated with hearing loss. We aimed to evaluate the genetic etiology of hearing loss in a family with moderate late-onset hearing loss using next-generation sequencing and to conduct a review of reported variants in the
gene. We identified a novel disease-causing variant in the
gene (NM_024915: c.1510C>T; p.Arg504Ter) in both affected members of the family. They both presented with moderate late-onset hearing loss with no additional clinical characteristics. Reviewing known
variants associated with hearing loss, we can conclude that they are more likely to be truncating variants, while the associated onset of hearing loss is variable.
Familial hypercholesterolemia (FH) is arguably the most common monogenic disorder in humans, but severely under-diagnosed. Individuals with untreated FH have an over 10-fold elevated risk of ...cardiovascular complications as compared to unaffected individuals; early diagnosis and timely management substantially reduce this risk.
Slovenia has gradually implemented the program of universal FH screening in pre-school children, consisting of a two step approach: (1) universal hypercholesterolemia screening in pre-school children at the primary care level; (2) genetic FH screening in children referred to the tertiary care level according to clinical guidelines (with additional cascade screening of family members). The program is presented in detail.
We analyzed retrospective data (2012–2016), to assess the efficiency of the universal FH screening program. In that period, 280 children (59.3% female) were referred to our center through the program for having TC > 6 mmol/L (231.7 mg/dL) or >5 mmol/L (193.1 mg/dL), with a positive family history of premature cardiovascular complications at the universal hypercholesterolemia screening.
170 (57.1% female) of them were fully genotyped, 44.7% had an FH disease-causing variant (28.8% in LDLR gene, 15.9% in APOB, none in PCSK9), one patient was LIPA positive, and 40.9% of the remaining patients carried an ApoE4 isoform; genetic analysis is still ongoing for one-third of the referred patients. For almost every child with confirmed FH, one parent had highly probable FH.
FH was confirmed in almost half of the referred children, detected through the universal screening for hypercholesterolemia.
•FH is a common monogenic disorder but severely under diagnosed and under treated.•FH screening in childhood with early treatment is needed.•Slovenia has a unique and effective program of universal FH screening in children.•Almost half of the children referred through the program had FH causing mutation.
Telomere attrition is increased in various disorders and is therefore a potential biomarker for diagnosis and/or prognosis of these disorders. The contribution of telomere attrition in the ...pathogenesis of neurodegenerative disorders is yet to be fully elucidated. We are reviewing the current knowledge regarding the telomere biology in two common neurodegenerative disorders, Alzheimer’s disease and Parkinson’s disease. Furthermore, we are discussing future prospective of telomere research in these disorders. The majority of studies reported consistent evidence of the accelerated telomere attrition in Alzheimer’s disease patients, possibly in association with elevated oxidative stress levels. On the other hand in Parkinson’s disease, various studies reported contradictory evidence regarding the telomere attrition. Consequently, due to the low specificity and sensitivity, the clinical benefit of telomere length as a biomarker of neurodegenerative disease development and progression is not yet recognized. Nevertheless, longitudinal studies in large carefully selected cohorts might provide further elucidation of the complex involvement of the telomeres in the pathogenesis of neurodegenerative diseases. Telomere length maintenance is a complex process characterized by environmental, genetic and epigenetic determinants. Thus, in addition to the selection of the study cohort, also the selection of analytical methods and types of biological samples for evaluation of the telomere attrition is of outmost importance.
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