Impact of genetic and non-genetic factors on phenotypic diversity in NBAS-associated disease.

Biallelic pathogenic variants in neuroblastoma-amplified sequence (NBAS) cause a pleiotropic multisystem disorder. Three clinical subgroups have been defined correlating with the localisation of pathogenic variants in the NBAS gene: variants affecting the C-terminal region of NBAS result in SOPH syndrome (short stature, optic atrophy, Pelger-Huët anomaly), variants affecting the Sec 39 domain are associated with infantile liver failure syndrome type 2 (ILFS2) and variants affecting the ß-propeller domain give rise to a combined phenotype. However, there is still unexplained phenotypic diversity across the three subgroups, challenging the current concept of genotype-phenotype correlations in NBAS-associated disease. Therefore, besides examining the genetic influence, we aim to elucidate the potential impact of pre-symptomatic diagnosis, emergency management and other modifying variables on the clinical phenotype. We investigated genotype-phenotype correlations in individuals sharing the same genotypes (n = 30 individuals), and in those sharing the same missense variants with a loss-of-function variant in trans (n = 38 individuals). Effects of a pre-symptomatic diagnosis and emergency management on the severity of acute liver failure (ALF) episodes also were analysed, comparing liver function tests (ALAT, ASAT, INR) and mortality. A strong genotype-phenotype correlation was demonstrated in individuals sharing the same genotype; this was especially true for the ILFS2 subgroup. Genotype-phenotype correlation in patients sharing only one missense variant was still high, though at a lower level. Pre-symptomatic diagnosis in combination with an emergency management protocol leads to a trend of reduced severity of ALF. High genetic impact on clinical phenotype in NBAS-associated disease facilitates monitoring and management of affected patients sharing the same genotype. Pre-symptomatic diagnosis and an emergency management protocol do not prevent ALF but may reduce its clinical severity.

Impact of Genotype, Serum Bile Acids, and Surgical Biliary Diversion on Native Liver Survival in FIC1 Deficiency.

BACKGROUND AND AIMS: Mutations in ATPase phospholipid transporting 8B1 (ATP8B1) can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1. The rarity of FIC1 deficiency has largely prevented a detailed analysis of its natural history, effects of predicted protein truncating mutations (PPTMs), and possible associations of serum bile acid (sBA) concentrations and surgical biliary diversion (SBD) with long-term outcome. We aimed to provide insights by using the largest genetically defined cohort of patients with FIC1 deficiency to date. APPROACH AND RESULTS: This multicenter, combined retrospective and prospective study included 130 patients with compound heterozygous or homozygous predicted pathogenic ATP8B1 variants. Patients were categorized according to the number of PPTMs (i.e., splice site, frameshift due to deletion or insertion, nonsense, duplication), FIC1-A (n = 67; no PPTMs), FIC1-B (n = 29; one PPTM), or FIC1-C (n = 34; two PPTMs). Survival analysis showed an overall native liver survival (NLS) of 44% at age 18 years. NLS was comparable among FIC1-A, FIC1-B, and FIC1-C (% NLS at age 10 years: 67%, 41%, and 59%, respectively; P = 0.12), despite FIC1-C undergoing SBD less often (% SBD at age 10 years: 65%, 57%, and 45%, respectively; P = 0.03). sBAs at presentation were negatively associated with NLS (NLS at age 10 years, sBAs < 194 µmol/L: 49% vs. sBAs ≥ 194 µmol/L: 15%; P = 0.03). SBD decreased sBAs (230 [125-282] to 74 [11-177] µmol/L; P = 0.005). SBD (HR 0.55, 95% CI 0.28-1.03, P = 0.06) and post-SBD sBA concentrations < 65 µmol/L (P = 0.05) tended to be associated with improved NLS. CONCLUSIONS: Less than half of patients with FIC1 deficiency reach adulthood with native liver. The number of PPTMs did not associate with the natural history or prognosis of FIC1 deficiency. sBA concentrations at initial presentation and after SBD provide limited prognostic information on long-term NLS.

Mucopolysaccharidosis-Plus Syndrome: Report on a Polish Patient with a Novel VPS33A Variant with Comparison with Other Described Patients.

Eleven patients from Yakutia with a new lysosomal disease assumed then as mucopolysaccharidosis-plus syndrome (MPS-PS) were reported by Gurinova et al. in 2014. Up to now, a total number of 39 patients have been reported; in all of them, the c.1492C>T (p.Arg498Trp) variant of the VPS33A gene was detected. Here, we describe the first Polish MPS-PS patient with a novel homozygous c.599G>C (p.Arg200Pro) VPS33A variant presenting over 12 years of follow-up with some novel clinical features, including fetal ascites (resolved spontaneously), recurrent joint effusion and peripheral edemas, normal growth, and visceral obesity. Functional analyses revealed a slight presence of chondroitin sulphate (only) in urine glycosaminoglycan electrophoresis, presence of sialooligosaccharides in urine by thin-layer chromatography, and normal results of lysosomal enzymes activity and lysosphingolipids concentration in dried blood spot. The comparison with other MPS-PS described cases was also provided. The presented description of the natural history of MPS-PS in our patient may broaden the spectrum of phenotypes in this disease.

Pharmacological chaperone therapy for the treatment of inborn errors of metabolism / Stosowanie farmakologicznych chaperonów w leczeniu wrodzonych chorób metabolicznych.

The article describes the mechanism of molecular and pharmacological chaperones in the treatment of inborn errors of metabolism. The literature review of the usage of ambroxol acting as a pharmacological chaperone for beta-glucocerebrosidase in Gaucher disease and Parkinson's disease associated with GBA variants has been reviewed.

Progressive familial intrahepatic cholestasis type 3: Report of four clinical cases, novel ABCB4 variants and long-term follow-up.

INTRODUCTION AND OBJECTIVES: Progressive familial intrahepatic cholestasis type 3 (PFIC-3) is a rare autosomal recessive cholestatic liver disorder caused by mutations in the ABCB4 gene. The aim of this study was to present the phenotypic and genotypic spectrum of 4 Polish PFIC-3 patients diagnosed in a one-referral centre. MATERIALS AND METHODS: The study included 4 patients with cholestasis and pathogenic variants in the ABCB4 gene identified by next-generation sequencing (NGS) of a targeted-gene panel or whole exome sequencing (WES). Clinical, laboratory, histological, and molecular data were collected. RESULTS: Four patients (three males) were identified. The age at first noted clinical signs and symptoms was 6, 2.5, 14, and 2 years respectively; the mean age was 6 years. Those signs and symptoms include pruritus (2 out of 4 patients) and hepatomegaly with splenomegaly (4 out of 4 patients). The age at the time of referral to our centre was 9, 3, 15, and 2.5 years respectively, while the mean age was 7 years. Chronic cholestatic liver disease of unknown aetiology was established in all of them. The NGS analysis was performed in all patients at the last follow-up visit. Three novel variants including c.902T>A, p.Met301Lys, c.3279+1G>A, p.?, and c.3524T>A, p.Leu1175His were identified. The time from the first consultation to the final diagnosis was 14, 9, 3, and 1 year respectively; the mean was 6.8 years. A detailed follow-up was presented. CONCLUSIONS: The clinical phenotype of PFIC-3 could be variable. The clinical and biochemical diagnosis of PFIC-3 is difficult, thus the NGS study is very useful in making a proper diagnosis.

NBAS deficiency due to biallelic c.2809C > G variant presenting with recurrent acute liver failure with severe hyperammonemia, acquired microcephaly and progressive brain atrophy.

Biallelic pathogenic variants in the neuroblastoma amplified sequence (NBAS) gene were firstly (2015) identified as a cause of fever-triggered recurrent acute liver failure (RALF). Since then, some patients with NBAS deficiency presenting with neurologic features, including a motor delay, intellectual disability, muscular hypotonia and a mild brain atrophy, have been reported. Here, we describe a case of pediatric patient diagnosed with NBAS deficiency due to a homozygous c.2809C > G, p.(Pro937Ala) variant presenting with RALF with severe hyperammonemia, acquired microcephaly and progressive brain atrophy. Not reported in the literature findings include severe hyperammonemia during ALF episode, and neurologic features in the form of acquired progressive microcephaly with brain atrophy. The latter raises the hypothesis about a primary neurologic phenotype in NBAS deficiency.

Disturbance of lipid homeostasis in lysosomal lipase deficiency ­ pathomechanism, diagnosis and treatment / Zaburzenie homeostazy lipidowej w deficycie lizosomalnej lipazy ­ patomechanizm, diagnostyka i leczenie.

Lysosomal acid lipase (LAL) plays a key role in lipid metabolism through the hydrolysis of cholesteryl esters and triglycerides in lysosomes. LAL deficiency is a rare autosomal recessive lysosomal storage disease caused by deleterious mutations in the LIPA gene. In the case of LAL deficiency, cholesteryl esters and triglycerides accumulate within the lysosomes. The up-regulation of endogenous cholesterol production, increased synthesis of apolipoprotein B (ApoB) and increased production of very-low-density lipoprotein cholesterol (VLDL-C) is observed. The diagnosis is easy due to the currently available method of testing the enzyme activity in a dry blood spot. Molecular analysis is necessary to verify the clinical and biochemical diagnosis and to analyze the genotype-phenotype correlation. Sebelipase alfa is a recombinant human lysosomal lipase intended for use in enzyme replacement therapy in patients with LAL deficiency.

Citrin deficiency ­ pathogenesis, clinical and biochemical manifestation, diagnostics, treatment / Deficyt cytrynu.

Citrin deficiency is an inherited metabolic disease caused by biallelic pathogenic variants in the SLC25A13 gene encoding the carrier protein called citrin. There are observed three characteristic clinical and biochemical age-dependent phenotypes: neonatal intrahepatic cholestasis caused by citrin deficiency, failure to thrive and dyslipidemia caused by citrin deficiency and adult-onset citrullinemia type 2. The paper presents the characteristics of the pathogenesis of citrin deficiency, clinical and biochemical delineation of individual phenotypes, differential diagnosis and treatment of citrin deficiency.

Genotype correlates with the natural history of severe bile salt export pump deficiency.

BACKGROUND & AIMS: Mutations in ABCB11 can cause deficiency of the bile salt export pump (BSEP), leading to cholestasis and end-stage liver disease. Owing to the rarity of the disease, the associations between genotype and natural history, or outcomes following surgical biliary diversion (SBD), remain elusive. We aimed to determine these associations by assembling the largest genetically defined cohort of patients with severe BSEP deficiency to date. METHODS: This multicentre, retrospective cohort study included 264 patients with homozygous or compound heterozygous pathological ABCB11 mutations. Patients were categorized according to genotypic severity (BSEP1, BSEP2, BSEP3). The predicted residual BSEP transport function decreased with each category. RESULTS: Genotype severity was strongly associated with native liver survival (NLS, BSEP1 median 20.4 years; BSEP2, 7.0 years; BSEP3, 3.5 years; p <0.001). At 15 years of age, the proportion of patients with hepatocellular carcinoma was 4% in BSEP1, 7% in BSEP2 and 34% in BSEP3 (p = 0.001). SBD was associated with significantly increased NLS (hazard ratio 0.50; 95% CI 0.27-0.94: p = 0.03) in BSEP1 and BSEP2. A serum bile acid concentration below 102 µmol/L or a decrease of at least 75%, each shortly after SBD, reliably predicted NLS of ≥15 years following SBD (each p <0.001). CONCLUSIONS: The genotype of severe BSEP deficiency strongly predicts long-term NLS, the risk of developing hepatocellular carcinoma, and the chance that SBD will increase NLS. Serum bile acid parameters shortly after SBD can predict long-term NLS. LAY SUMMARY: This study presents data from the largest genetically defined cohort of patients with severe bile salt export pump deficiency to date. The genotype of patients with severe bile salt export pump deficiency is associated with clinical outcomes and the success of therapeutic interventions. Therefore, genotypic data should be used to guide personalized clinical care throughout childhood and adulthood in patients with this disease.

Controlled attenuation parameter and liver stiffness measurements using transient elastography by FibroScan in Gaucher disease.

BACKGROUND: Liver involvement in Gaucher disease (GD) is a result of glucosylceramide (GL1) and its deacylated lysolipid, glucosylsphingosine (lyso-GL1) infiltration of macrophages. The long-term liver-related complications of GD could include liver fibrosis and cirrhosis. The aim of the study was to evaluate clinical utility and relevance of TE by FibroScan in GD patients by assessing two parameters: controlled attenuation parameter (CAP) and liver stiffness (LS), in regard of GD-related variables, type of GD, age of patients, enzymatic replacement therapy (ERT), and metabolic features. METHODS: 59 Polish patients (55 adults, 4 children) with GD (43 patients with type 1 and 16 patients with type 3) aged 7-86 years, underwent TE by FibroScan; elevated CAP was defined as >250 dB/m and elevated LS as >7 kPa. All patients, except five patients with type 1 GD (patients' refusal), were treated by ERT. RESULTS: Elevated CAP was present in 23% of GD1 patients and 19% of GD3 patients. Elevated LS was present in 21% of GD1 patients and 13% of GD3 patients. CAP was fairly, positively (ρ = 0.356) correlated with BMI. LS was fairly, positively (ρ = 0.4) correlated with patient's age, as well as the age at start of ERT (ρ = 0.326). CAP was strongly, negatively (ρ = -0.52) correlated with the age at start of ERT. LS and CAP were correlated (strongly, positively) only in GD3. CONCLUSIONS: TE by FibroScan could be considered as an additional method for evaluating GD patients for non-invasive assessment of CAP and LS. The investigation of serial TE measurements in untreated as well as treated GD patients is needed to better determine whether this technology should be added to recommendations for monitoring GD patients. TE by FibroScan could be performed in GD patients with increased BMI and especially those with metabolic syndrome as they have other important risks for liver disease. After our analysis we think these risks factors are independent of GD but still very important for their overall health.

Liver involvement in NGLY1 congenital disorder of deglycosylation.

N-glycanase 1 deficiency is a congenital disorder of deglycosylation, which has been diagnosed in 27 patients, including 2 of them from Poland. The most characteristic symptoms include global developmental disability, hyperkinetic movement disorder, hypo-/alacrimia, and elevated serum transaminases. We reported on a patient in whom the liver biopsy done at the age of 3 years revealed the presence of steatosis, fibrosis, and an amorphous periodic acid-Schiff staining positive diastases-digested material in the cytoplasm.

Congenital disorder of deglycosylation associated with N-glycanse 1 deficiency / Wrodzone zaburzenie deglikozylacji zwiazane z deficytem N-glikanazy 1.

Together with the lysosomal storage diseases, N-glycanase 1 deficiency is a congenital disorder of deglycosylation, which has been diagnosed in 27 patients, including two of them from Poland. The pathogenesis remains unknown, however, the main role is attributed to the disturbed endoplasmic reticulum-associated protein degradation process. The most characteristic symptoms include global developmental disability, hyperkinetic movement disorder, hypo-/alacrimia, and elevated serum transaminases. Identification of pathogenic variants in the NGLY1 gene is required to confirm the diagnosis.

Long-term follow-up in children with progressive familial intrahepatic cholestasis type 2 after partial external biliary diversion with focus on histopathological features.

Progressive familial intrahepatic cholestasis (PFIC) comprises a group of rare cholestatic liver disorders of childhood that could lead to liver cirrhosis. Nowadays, the partial biliary diversion procedure is still a therapeutic option in non-cirrhotic children with PFIC1 or PFIC2 after an ineffective ursodeoxycholic acid (UDCA) therapy. However, the relevant disadvantage of the partial external biliary diversion (PEBD) is that adolescent patients could not accept a permanent stoma. In some of them, despite of good clinical and biochemical results of this procedure, the ileal exclusion (IE) procedure had to be performed many years after PEBD. Our aims were to find the most characteristic early microscopic features of the disease as well as to compare changes in the liver biopsy specimens at the time of diagnosis and long-time (more than 10 years) after a surgical procedure. We examined retrospectively 8 liver biopsies from 4 PFIC2 patients comparing the results from the first biopsies done at the time of PFIC diagnosis and the second ones, done many years after PEBD. The characteristic lobular rosette formations of hepatocytes were found in all patients at the time of diagnosis. Cholestasis was observed in each patient, but only in two of them, centrally located bile plugs were found. The majority of hepatocytes showed degenerative changes from mild to severe degree. In the follow-up biopsies, cholestasis completely disappeared in 3 patients and decreased significantly in 1 other patient. Based on Batts and Ludwig fibrosis scoring system, the liver fibrosis had resolved in two out of three patients. The formation of lobular rosettes with centrally located bile plugs and degenerative changes of hepatocytes seem to be the most characteristic microscopic features in early liver biopsies in PFIC2 patients. Partial external biliary diversion significantly improved the clinical, anthropological, biochemical as well histological outcome of the patients.

Diagnostic Algorithm for Cholesteryl Ester Storage Disease: Clinical Presentation in 19 Polish Patients.

BACKGROUND: Lysosomal acid lipase deficiency (LAL-D) is a rare autosomal recessive lysosomal lipid storage disorder that results in an early-onset, severe, and lethal phenotype, known as Wolman disease, or a late-onset, attenuated phenotype, cholesteryl ester storage disease (CESD). The aim of our study was to describe the clinical presentation of CESD, focusing on the first noted abnormalities in patients. A diagnostic algorithm of CESD was also proposed. METHODS: This is an observational, 1-center study of 19 Polish patients with late-onset LAL-D. RESULTS: The mean age at which the first symptoms were reported was 4 years and 6 months. A mild hepatomegaly was the most common initial abnormality observed in all (100%) patients. Seven (37%) patients were noted to have mildly to moderately elevated serum transaminases. At the time of first hospitalization all (100%) patients presented with hepatomegaly, 15 (79%) patients presented with elevated serum transaminases and all (100%) patients had dyslipidemia. The mean age at the time of CESD diagnosis was 7 years and 2 months. Diagnoses were based on a deficient LAL activity in leukocytes (in all patients) and the LIPA gene mutations (in 47% of them). All the patients were carriers for the mutation c.894G>A in the LIPA gene. There was approximately a 3-year delay from initial symptoms to final diagnosis. CONCLUSIONS: Hepatomegaly constitutes the most common presenting clinical sign of CESD. Hepatomegaly and dyslipidemia defined as elevated serum total and LDL cholesterol, elevated triglycerides and normal to low HDL cholesterol, comprises the most characteristic findings at CESD diagnosis.

[Progressive familial intrahepatic cholestasis type 3].

Progressive familial intrahepatic cholestasis is caused by mutations in the ABCB4 gene and belongs to the family of familial intrahepatic cholestais disorders inherited in an autosomal recessive pattern. To date, about 200 patients with various hepatobiliary disorders associated with ABCB4 gene mutations have been described in the literature. The aim of this manuscript was to describe the pathogenesis, clinical presentation, diagnostic process and treatment of progressive familial intrahepatic cholestais type 3, based on the literature review.

[Transaldolase deficiency - clinical outcome, pathogenesis, diagnostic process].

Transaldolase deficiency is a rare inborn autosomal recessive error of the pentose phosphate pathway that, to date, has been diagnosed in 33 patients, including 4 from Poland. The aim of this manuscript was to present the clinical presentation, pathogenesis and diagnostic process of transaldolase deficiency. The authors also present a diagnostic algorithm of transaldolase deficiency.

Cortisol deficiency as a rare cause of neonatal cholestasis.

Cortisol deficiency constitutes a rare cause of neonatal cholestasis. The aim of this manuscript was to present the pathogenesis of cortisol deficiency in neonatal cholestasis. The authors also present the characteristics of selected disorders resulting in cortisol deficiency.

The Liver and Lysosomal Storage Diseases: From Pathophysiology to Clinical Presentation, Diagnostics, and Treatment.

The liver, given its role as the central metabolic organ, is involved in many inherited metabolic disorders, including lysosomal storage diseases (LSDs). The aim of this manuscript was to provide a comprehensive overview on liver involvement in LSDs, focusing on clinical manifestation and its pathomechanisms. Gaucher disease, acid sphingomyelinase deficiency, and lysosomal acid lipase deficiency were thoroughly reviewed, with hepatic manifestation being a dominant clinical phenotype. The natural history of liver disease in the above-mentioned lysosomal disorders was delineated. The importance of Niemann-Pick type C disease as a cause of cholestatic jaundice, preceding neurological manifestation, was also highlighted. Diagnostic methods and current therapeutic management of LSDs were also discussed in the context of liver involvement.

Characteristics of Neuroimaging and Behavioural Phenotype in Polish Patients with PIGV-CDG-An Observational Study and Literature Review.

Congenital disorders of glycosylation (CDGs) are a wide group of genetic diseases characterised by a severe clinical spectrum, consisting of developmental delays, dysmorphisms, and neurological deficits. Mutations in the PIGV gene lead to a disorder called hyperphosphatasia with impaired intellectual development syndrome 1 (HPMRS1), distinct from other CDGs in terms of hyperphosphatemia related to abnormal ALP activity and brachytelephalangy. This article discusses the phenotype of six Polish patients with HPMRS1 with a special focus on behavioural and imaging features, which were not addressed in 26 previously reported cases. The medical records of six patients aged 6 to 22 years were collected and analysed. In all cases, the same PIGV homozygotic mutation (c.1022C>A; p.Ala341Glu) was found, although the patients presented a diverse spectrum of neurological and developmental disorders, concerning in most cases the muscular tonus and general developmental delay. The most prevalent dysmorphic features included hypertelorism, high palate, and finger anomalies, whereas other characteristics present in all previously described cases, such as a short, broad nose and brachytelephalangy, were less frequently observed. Similarly to previous reports, the magnetic resonance (MR) and computed tomography (CT) head scans returned varied results, including physiological and pathological brain images in equal measure, the latter of which consisted of cortical atrophy, delayed myelination, hydrocephalus, and hypoplastic corpus callosum. Each patient exhibited symptoms characteristic of autism spectrum disorders, especially in terms of attention deficits, as well as controlling and expressing emotions. The most common type of sensory processing disorder was over-responsivity. Despite the low prevalence of HPMRS1, the patients reported in the literature presented a rather uniform phenotype, which does not correspond with the one found in each individual of the studied group. Behavioural disorders and sensory impairment require additional care and awareness considering the global developmental delay often observed in these patients.

A 20-Year Longitudinal Study of Plasma Chitotriosidase Activity in Treated Gaucher Disease Type 1 and 3 Patients-A Qualitative and Quantitative Approach.

Chitotriosidase is an enzyme produced and secreted in large amounts by activated macrophages, especially macrophages loaded with phagocytozed glycosphingolipid in Gaucher disease. Macrophages phagocytose decayed blood cells that contain a lot of sphingolipid-rich cell membranes. In Gaucher disease, due to a deficit in beta-glucocerebrosidase activity, the phagocytozed substrate glucocerebroside cannot undergo further catabolism. In such a situation, macrophages secrete chitotriosidase in proportion to the degree of overload. Gaucher disease (GD) is a recessively inherited disorder resulting in storage of glucosylceramide (GlcCer) in lysosomes of tissue macrophages. It is directly caused by the deficiency of beta-glucocerebrosidase (GBA) activity. Chitotriosidase has been measured systematically each year in the same group of 49 patients with type 1 and 3 GD for over 20 years. Our analysis showed that chitotriosidase is very sensitive biomarker to enzyme replacement therapy (ERT). The response to treatment introduction is of an almost immediate nature, lowering pathologically high chitotriosidase levels by a factor of 2 in a time scale of 8 months, on average. Long term enzyme replacement therapy (ERT) brings chitotriosidase activity close to reference values. Finally, reducing the dose of ERT quickly boosts chitotriosidase activity, but restoring the initial dose of treatment brings chitotriosidase level of activity back onto the decreasing time trajectory.