Women with Gaucher Disease.

Gaucher disease is an inherited disorder in which there is a deficiency of the enzyme glucocerebrosidase, which leads to the accumulation of glucosylceramide. Although much scientific evidence is now available, there is still limited data on the impact on the different life stages of women with this disease. Among other alterations, a delay in menarche has been described, although it has not been related to fertility problems. Menorrhagia is relatively frequent, being related to the presence of thrombocytopenia, thrombocytopathies or coagulation disorders. On the other hand, pregnancy planning is an increasingly frequent concern. All patients should undergo genetic counseling, and it is important to monitor the appearance or worsening of organomegaly, bone and hematologic abnormalities to establish clinical and therapeutic recommendations. Management during the puerperium will depend on the evolution of gestation, and, during the lactation period, the potential appearance of bone complications should be assessed. An early onset of menopause, compared to the general population, has also been described, which may accelerate the development of osteopenia. Finally, although the usual screening protocols for neoplasms are currently being performed, it is recommended to watch for early signs of liver or renal neoplasms when examining the results of imaging tests performed during evaluations for this disease.

Management of phenylketonuria in European PKU centres remains heterogeneous.

Phenylketonuria (PKU) is a genetic disorder that follows an autosomal recessive inheritance pattern. Dietary treatment is the cornerstone of therapy and is based on natural protein restriction, Phe-free L-amino acid supplements (protein substitutes) and low protein foods. The aim of this project was to collect information about the clinical management of patients with PKU, focusing on understudied or unresolved issues such as blood phenylalanine (Phe) fluctuations and clinical symptoms, particularly gastro intestinal (GI) discomfort and sleep problems. The survey consisted of 10 open-ended and 12 multiple-choice questions that collected information about size of the PKU population in each center, the center's clinical practices and the outcomes observed by the center concerning adherence, clinical and biochemical abnormalities and clinical symptoms (GI and sleep). The questionnaire was sent to 72 experts from metabolic centers in 11 European countries. Thirty-three centers answered. The results of this survey provide information about the clinical practice in different age groups, concentrating on dietary tolerance, treatment adherence, and metabolic control. All the centers prescribed a Phe-restricted diet, with Phe-free/low Phe protein substitutes and low protein foods. Daily doses given of protein substitutes varied from 1 to 5, with adherence to the prescribed amounts decreasing with increasing age. Respondents identified that improvement in the flavor, taste, volume and smell of protein substitutes may improve adherence. Finally, the survey showed that clinical symptoms, such as GI discomfort and sleep problems occur in patients with PKU but are not systematically evaluated. Twenty-four-hour Phe fluctuations were not routinely assessed. The results highlight a strong heterogeneity of approach to management despite international PKU guidelines. More clinical attention should be given to gastrointestinal and sleep problems in PKU.

Parent knowledge regarding food selection for children with PKU: Results of a survey in the United States.

OBJECTIVES: Dietary treatment is the main therapy for most patients with phenylketonuria (PKU). Parental knowledge regarding food selection is crucial to ensure adequate metabolic control and brain development during childhood and to promote lifelong adherence and healthy dietary behavior in the offspring. The aims of this study were to assess whether parental or caregiver knowledge regarding nutritional selection for children with PKU is in accordance with medical recommendations and to evaluate factors that influence their level of knowledge. METHODS: This was a cross-sectional observational study. An online or paper survey (N = 178) was distributed throughout the United States. The survey included a validated food selection questionnaire to assess whether the respondent adequately identified foods that require certain restrictions versus foods that can be consumed freely by an individual with PKU. RESULTS: General knowledge of food selection among the caregivers was very high or high in nearly 60% (60-98th score percentile). Participants with the lowest scores in general knowledge of the PKU diet (quartile 1) were more likely to label allowed foods incorrectly. Respondents with the highest scores (quartile 4) were more likely to label limited foods correctly but incorrectly label allowed items. CONCLUSION: Knowledge of restricted foods is important to avoid poor metabolic control, but knowledge of allowed foods can be just as important to allow for a diet that is diverse, palatable, and nutritionally balanced.

Clinical Outcomes of Patients with Chronic Neuropathic Form of Gaucher Disease in the Spanish Real-World Setting: A Retrospective Study.

This was a retrospective, multicenter study that aimed to report the characteristics of type 3 Gaucher disease (GD3) patients in Spain, including the genotype, phenotype, therapeutic options, and treatment responses. A total of 19 patients with GD3 from 10 Spanish hospitals were enrolled in the study (14 men, 5 women). The median age at disease onset and diagnosis was 1 and 1.2 years, respectively, and the mean age at follow-up completion was 12.37 years (range: 1-25 years). Most patients exhibited splenomegaly (18/19) and hepatomegaly (17/19) at the time of diagnosis. The most frequent neurological abnormalities at onset were psychomotor retardation (14/19) and extrinsic muscle disorders (11/19), including oculomotor apraxia, supranuclear palsy, and strabismus. The L444P (c.1448T>C) allele was predominant, with the L444P (c.1448T>C) homozygous genotype mainly associated with visceral manifestations like hepatosplenomegaly, anemia, and thrombocytopenia. All patients received enzyme replacement therapy (ERT); other treatments included miglustat and the chaperone (ambroxol). Visceral manifestations, including hepatosplenomegaly and hematological and bone manifestations, were mostly controlled with ERT, except for kyphosis. The data from this study may help to increase the evidence base on this rare disease and contribute to improving the clinical management of GD3 patients.

Newborn screening for propionic, methylmalonic acidemia and vitamin B12 deficiency. Analysis of 588,793 newborns.

OBJECTIVES: We present the results of our experience in the diagnosis and follow up of the positive cases for propionic, methylmalonic acidemias and cobalamin deficiencies (PA/MMA/MMAHC) since the Expanded Newborn Screening was implemented in Madrid Region. METHODS: Dried blood samples were collected 48 h after birth. Amino acids and acylcarnitines were quantitated by MS/MS. Newborns with alterations were referred to the clinical centers for follow-up. Biochemical and molecular genetic studies for confirmation of a disease were performed. RESULTS: In the period 2011-2020, 588,793 children were screened, being 953 of them were referred to clinical units for abnormal result (192 for elevated C3 levels). Among them, 88 were false positive cases, 85 maternal vitamin B12 deficiencies and 19 were confirmed to suffer an IEM (8 PA, 4 MMA, 7 MMAHC). Ten out 19 cases displayed symptoms before the NBS results (6 PA, 1 MMA, 3 MMAHC). C3, C16:1OH+C17 levels and C3/C2 and C3/Met ratios were higher in newborns with PA/MMA/MMAHC. Cases diagnosed with B12 deficiency had mean B12 levels of 187.6 ± 76.9 pg/mL and their mothers 213.7 ± 95.0; 5% of the mothers were vegetarian or had poor eating while 15% were diagnosed of pernicious anemia. Newborns and their mothers received treatment with B12 with different posology, normalizing their levels and the secondary alterations disappeared. CONCLUSIONS: Elevated C3 are a frequent cause for abnormal result in newborn screening with a high rate of false positive cases. Presymptomatic diagnosis of most of PA and some MMA/MMAHC is difficult. Vitamin B12 deficiency secondary to maternal deprivation is frequent with an heterogenous clinical and biochemical spectrum.

Plasma CoQ10 Status in Patients with Propionic Acidaemia and Possible Benefit of Treatment with Ubiquinol.

Propionic acidaemia (PA) is an innate error of metabolism involving a deficiency in the enzyme propionyl-CoA carboxylase. Better control of acute decompensation episodes together with better treatment and monitoring have improved the prognosis of patients with this problem. However, long-term complications can arise in those in whom good metabolic control is achieved, the result of mitochondrial dysfunction caused by deficient anaplerosis, increased oxidative stress, and reduced antioxidative capacity. Coenzyme Q10 (CoQ10) is a nutritional supplement that has a notable antioxidative effect and has been shown to improve mitochondrial function. The present prospective, interventional study examines the plasma concentration of CoQ10 in patients with PA, their tolerance of such supplementation with ubiquinol, and its benefits. Seven patients with PA (aged 2.5 to 20 years, 4 males) received supplements of CoQ10 in the form of ubiquinol (10 mg/kg/day for 6 months). A total of 6/7 patients showed reduced plasma CoQ10 concentrations that normalized after supplementation with ubiquinol (p-value < 0.001), which was well tolerated. Urinary citrate levels markedly increased during the study (p-value: 0.001), together with elevation of citrate/methlycitrate ratio (p-value: 0.03). No other significant changes were seen in plasma or urine biomarkers of PA. PA patients showed a deficiency of plasma CoQ10, which supplementation with ubiquinol corrected. The urinary excretion of Krebs cycle intermediate citrate and the citrate/methylcitrate ratio significantly increased compared to the baseline, suggesting improvement in anaplerosis. This treatment was well tolerated and should be further investigated as a means of preventing the chronic complications associated with likely multifactorial mitochondrial dysfunction in PA.

Management of early treated adolescents and young adults with phenylketonuria: Development of international consensus recommendations using a modified Delphi approach.

BACKGROUND: Early treated patients with phenylketonuria (PKU) often become lost to follow-up from adolescence onwards due to the historical focus of PKU care on the pediatric population and lack of programs facilitating the transition to adulthood. As a result, evidence on the management of adolescents and young adults with PKU is limited. METHODS: Two meetings were held with a multidisciplinary international panel of 25 experts in PKU and comorbidities frequently experienced by patients with PKU. Based on the outcomes of the first meeting, a set of statements were developed. During the second meeting, these statements were voted on for consensus generation (≥70% agreement), using a modified Delphi approach. RESULTS: A total of 37 consensus recommendations were developed across five areas that were deemed important in the management of adolescents and young adults with PKU: (1) general physical health, (2) mental health and neurocognitive functioning, (3) blood Phe target range, (4) PKU-specific challenges, and (5) transition to adult care. The consensus recommendations reflect the personal opinions and experiences from the participating experts supported with evidence when available. Overall, clinicians managing adolescents and young adults with PKU should be aware of the wide variety of PKU-associated comorbidities, initiating screening at an early age. In addition, management of adolescents/young adults should be a joint effort between the patient, clinical center, and parents/caregivers supporting adolescents with gradually gaining independent control of their disease during the transition to adulthood. CONCLUSIONS: A multidisciplinary international group of experts used a modified Delphi approach to develop a set of consensus recommendations with the aim of providing guidance and offering tools to clinics to aid with supporting adolescents and young adults with PKU.

Recommendations for the Diagnosis and Therapeutic Management of Hyperammonaemia in Paediatric and Adult Patients.

Hyperammonaemia is a metabolic derangement that may cause severe neurological damage and even death due to cerebral oedema, further complicating the prognosis of its triggering disease. In small children it is a rare condition usually associated to inborn errors of the metabolism. As age rises, and especially in adults, it may be precipitated by heterogeneous causes such as liver disease, drugs, urinary infections, shock, or dehydration. In older patients, it is often overlooked, or its danger minimized. This protocol was drafted to provide an outline of the clinical measures required to normalise ammonia levels in patients of all ages, aiming to assist clinicians with no previous experience in its treatment. It is an updated protocol developed by a panel of experts after a review of recent publications. We point out the importance of frequent monitoring to assess the response to treatment, the nutritional measures that ensure not only protein restriction but adequate caloric intake and the need to avoid delays in the use of specific pharmacological therapies and, especially, extrarenal clearance measures. In this regard, we propose initiating haemodialysis when ammonia levels are >200−350 µmol/L in children up to 18 months of age and >150−200 µmol/L after that age.

Vitamin C and folate status in hereditary fructose intolerance.

BACKGROUND: Hereditary fructose intolerance (HFI) is a rare inborn error of fructose metabolism caused by the deficiency of aldolase B. Since treatment consists of a fructose-, sucrose- and sorbitol-restrictive diet for life, patients are at risk of presenting vitamin deficiencies. Although there is no published data on the status of these vitamins in HFI patients, supplementation with vitamin C and folic acid is common. Therefore, the aim of this study was to assess vitamin C and folate status and supplementation practices in a nationwide cohort of HFI patients. METHODS: Vitamin C and folic acid dietary intake, supplementation and circulating levels were assessed in 32 HFI patients and 32 age- and sex-matched healthy controls. RESULTS: Most of the HFI participants presented vitamin C (96.7%) and folate (90%) dietary intake below the recommended population reference intake. Up to 69% received vitamin C and 50% folic acid supplementation. Among HFI patients, 15.6% presented vitamin C and 3.1% folate deficiency. The amount of vitamin C supplementation and plasma levels correlated positively (R = 0.443; p = 0.011). Interestingly, a higher percentage of non-supplemented HFI patients were vitamin C deficient when compared to supplemented HFI patients (30% vs. 9.1%; p = 0.01) and to healthy controls (30% vs. 3.1%; p < 0.001). CONCLUSIONS: Our results provide evidence for the first time supporting vitamin C supplementation in HFI. There is great heterogeneity in vitamin supplementation practices and, despite follow-up at specialised centres, vitamin C deficiency is common. Further research is warranted to establish optimal doses of vitamin C and the need for folic acid supplementation in HFI.

Mitochondrial bioenergetic is impaired in Monocarboxylate transporter 1 deficiency: a new clinical case and review of the literature.

BACKGROUND: Monocarboxylate transporter 1 (MCT1) deficiency has recently been described as a rare cause of recurrent ketosis, the result of impaired ketone utilization in extrahepatic tissues. To date, only six patients with this condition have been identified, and clinical and biochemical details remain incomplete. RESULTS: The present work reports a patient suffering from severe, recurrent episodes of metabolic acidosis and psychomotor delay, showing a pathogenic loss-of-function variation c.747_750del in homozygosity in SLC16A1 (which codes for MCT1). Persistent ketotic and lactic acidosis was accompanied by an abnormal excretion of organic acids related to redox balance disturbances. Together with an altered bioenergetic profile detected in patient-derived fibroblasts, this suggests possible mitochondrial dysfunction. Brain MRI revealed extensive, diffuse bilateral, symmetric signal alterations for the subcortical white matter and basal ganglia, together with corpus callosum agenesia. CONCLUSIONS: These findings suggest that the clinical spectrum of MCT1 deficiency not only involves recurrent atacks of ketoacidosis, but may also cause lactic acidosis and neuromotor delay with a distinctive neuroimaging pattern including agenesis of corpus callosum and other brain signal alterations.

Diagnosis of inborn errors of metabolism within the expanded newborn screening in the Madrid region.

We present the results of our experience in the diagnosis of inborn errors of metabolism (IEM) since the Expanded Newborn Screening was implemented in our Region. Dried blood samples were collected 48 h after birth. Amino acids and acylcarnitines were quantitated by mass spectrometry (MS)/MS. Newborns with alterations were referred to the clinical centers for follow-up. Biochemical and molecular genetic studies for confirmation of a disease were performed. In the period 2011 to 2019, 592 822 children were screened: 902 of them were referred for abnormal results. An IEM was confirmed in 222 (1/2670): aminoacidopathies: 89 hyperphenylalaninemia (HPA) (51 benign HPA, 32 phenylketonuria, 4 DNAJC12 defect, and 2 primapterinuria), 6 hypermethioninemia, 3 tyrosinemia type 1 (TYR-1), 1 TYR-3, 4 maple syrup urine disease (MSUD), 2 branched-chain amino acid transferase 2 deficiency, 2 homocystinuria, 1 cystinuria, 2 ornithine transcarbamylase (OTC) deficiency, 2 citrullinemia type I (CTLN1); FAO defects: 43 medium-chain acyl-CoA dehydrogenase deficiency (MCADD), 13 very long-chain acyl-CoA dehydrogenase deficiency, 2 long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD), 1 multiple acyl-coA dehydrogenation deficiency, 11 systemic primary carnitine deficiency, 2 carnitine palmitoyltransferase type 2 (CPT-II) deficiency, 1 CPT-I deficiency; organic acidurias: 12 glutaric aciduria type 1 (GA-1), 4 methylmalonic acidemia (MMA), 7 MMA including combined cases with homocystinuria (MMAHC), 6 propionic acidemia (PA), 7 3-methylcrotonyl-CoA carboxylase, 1 3-hydroxy-3-methylglutaryl-CoA lyase deficiency lyase deficiency. Only 19 infants (8.5%) were symptomatic at newborn screening result (1 LCHADD, 5 PA, 1 CPT-II deficiency, 1 MMA, 3 MMAHC, 2 MSUD, 2 OTC deficiency, 1 CTLN1, 1 MCADD, 2 TYR-1). No false negative cases were identified. Genetic diagnosis was conclusive in all biochemically confirmed cases, except for two infants with HPA, identifying pathogenic variants in 32 different genes. The conditions with the highest incidence were HPA (1/6661) and MCAD deficiencies (1/13 787).

Interorgan amino acid interchange in propionic acidemia: the missing key to understanding its physiopathology.

BACKGROUND: Propionic acidemia is an inborn error of metabolism caused by a deficiency in the mitochondrial enzyme propionyl-CoA carboxylase that converts the propionyl CoA to methyl malonyl CoA. This leads to profound changes in distinct metabolic pathways, including the urea cycle, with consequences in ammonia detoxification. The implication of the tricarboxylic acid cycle is less well known, but its repercussions could explain both some of the acute and long-term symptoms of this disease. MATERIALS AND METHODS: The present observational study investigates the amino acid profiles of patients with propionic acidemia being monitored at the Hospital Ramón y Cajal (Madrid, Spain), between January 2015 and September 2017, comparing periods of metabolic stability with those of decompensation with ketosis and/or hyperammonemia. RESULTS: The concentrations of 19 amino acids were determined in 188 samples provided by 10 patients. We identified 40 metabolic decompensation episodes (22 only with ketosis and 18 with hyperammonemia). Plasma glutamine and alanine levels were reduced during these metabolic crises, probably indicating deficiency of anaplerosis (p < 0.001 for both alanine and glutamine). Hypocitrulllinemia and hypoprolinemia were also detected during hyperammonemia (p < 0.001 and 0.03, respectively). CONCLUSIONS: The amino acid profile detected during decompensation episodes suggests deficient anaplerosis from propionyl-CoA and its precursors, with implications in other metabolic pathways like synthesis of urea cycle amino acids and ammonia detoxification.

Serum zinc and copper in people with COVID-19 and zinc supplementation in parenteral nutrition.

OBJECTIVES: Zinc and copper are important to protect cells from oxidative stress and to enhance immunity. An association between low zinc levels and the severity of acute respiratory distress syndrome has been shown for people with COVID-19. We aimed to study serum zinc and copper concentrations in people with severe COVID-19 and zinc supplementation in parenteral nutrition (PN). METHODS: Thirty-five people with COVID-19 in need of PN were studied in a retrospective design. Serum samples were collected at three time points: at the start of PN, between 3 and 7 d after, and at the end of PN. RESULTS: Participants were on PN for a mean of 14 d, with a mean (± SD) daily supplemental zinc of 14.8 ± 3.7 mg/d. Serum zinc increased during PN administration from 98.8 ± 22.8 to 114.1 ± 23.3 µg/dL (Wilks' λ = 0.751, F = 5.459, P = 0.009). Conversely, serum copper did not vary from baseline (107.9 ± 34.2 µg/dL) to the end of the study (104.5 ± 37.4 µg/dL, Wilks' λ = 0.919, F = 1.453, P = 0.248). Serum zinc within the first week after starting PN and at the end of PN inversely correlated with total hospital stay (r = -0.413, P = 0.014, and r = -0.386, P = 0.022, respectively). Participants in critical condition presented lower serum copper (z = 2.615, P = 0.007). Mortality was not associated with supplemental zinc or with serum zinc or copper concentrations at any time of the study (P > 0.1 for all analyses). CONCLUSIONS: Serum zinc concentrations during PN support were inversely associated with length of hospital stay but not with mortality. Serum copper concentrations were lower in participants in critical condition but not associated with prognosis.

Stress Hyperglycemia and Osteocalcin in COVID-19 Critically Ill Patients on Artificial Nutrition.

We aimed to study the possible association of stress hyperglycemia in COVID-19 critically ill patients with prognosis, artificial nutrition, circulating osteocalcin, and other serum markers of inflammation and compare them with non-COVID-19 patients. Fifty-two critical patients at the intensive care unit (ICU), 26 with COVID-19 and 26 non-COVID-19, were included. Glycemic control, delivery of artificial nutrition, serum osteocalcin, total and ICU stays, and mortality were recorded. Patients with COVID-19 had higher ICU stays, were on artificial nutrition for longer (p = 0.004), and needed more frequently insulin infusion therapy (p = 0.022) to control stress hyperglycemia. The need for insulin infusion therapy was associated with higher energy (p = 0.001) and glucose delivered through artificial nutrition (p = 0.040). Those patients with stress hyperglycemia showed higher ICU stays (23 ± 17 vs. 11 ± 13 days, p = 0.007). Serum osteocalcin was a good marker for hyperglycemia, as it inversely correlated with glycemia at admission in the ICU (r = -0.476, p = 0.001) and at days 2 (r = -0.409, p = 0.007) and 3 (r = -0.351, p = 0.049). In conclusion, hyperglycemia in critically ill COVID-19 patients was associated with longer ICU stays. Low circulating osteocalcin was a good marker for stress hyperglycemia.

Transferrin Isoforms, Old but New Biomarkers in Hereditary Fructose Intolerance.

Hereditary Fructose Intolerance (HFI) is an autosomal recessive inborn error of metabolism characterised by the deficiency of the hepatic enzyme aldolase B. Its treatment consists in adopting a fructose-, sucrose-, and sorbitol (FSS)-restrictive diet for life. Untreated HFI patients present an abnormal transferrin (Tf) glycosylation pattern due to the inhibition of mannose-6-phosphate isomerase by fructose-1-phosphate. Hence, elevated serum carbohydrate-deficient Tf (CDT) may allow the prompt detection of HFI. The CDT values improve when an FSS-restrictive diet is followed; however, previous data on CDT and fructose intake correlation are inconsistent. Therefore, we examined the complete serum sialoTf profile and correlated it with FSS dietary intake and with hepatic parameters in a cohort of paediatric and adult fructosemic patients. To do so, the profiles of serum sialoTf from genetically diagnosed HFI patients on an FSS-restricted diet (n = 37) and their age-, sex- and body mass index-paired controls (n = 32) were analysed by capillary zone electrophoresis. We found that in HFI patients, asialoTf correlated with dietary intake of sucrose (R = 0.575, p < 0.001) and FSS (R = 0.475, p = 0.008), and that pentasialoTf+hexasialoTf negatively correlated with dietary intake of fructose (R = -0.386, p = 0.024) and FSS (R = -0.400, p = 0.019). In addition, the tetrasialoTf/disialoTf ratio truthfully differentiated treated HFI patients from healthy controls, with an area under the ROC curve (AUROC) of 0.97, 92% sensitivity, 94% specificity and 93% accuracy.

Development of a practical dietitian road map for the nutritional management of phenylketonuria (PKU) patients on pegvaliase.

Background: The metabolic dietitian/nutritionist (hereafter 'dietitian') plays an essential role in the nutritional management of patients with phenylketonuria (PKU), including those on pegvaliase. Currently, more educational support and clinical experience is needed to ensure that dietitians are prepared to provide optimal nutritional management and counselling of pegvaliase-treated patients. Methods: Via a face-to-face data-review meeting, followed by a virtual consolidation meeting, a group of expert dietitians and one paediatrician discussed and developed a series of recommendations on the nutritional evaluation and management of patients receiving pegvaliase. The consensus group consisted of 10 PKU experts: six dietitians and one paediatrician from Europe and three dietitians from the US. One European and three US dietitians had experience with pegvaliase-treated patients. Results: The consensus group recommended that a physician, dietitian and nurse are part of the pegvaliase treatment team. Additionally, a psychologist/counsellor should be included if available. Practical proposals for the nutritional evaluation of pegvaliase-treated patients at baseline, during the induction and titration phases and for long-term maintenance were developed. The consensus group suggested assessment of blood Phe at least monthly or every 2 weeks in the event of low blood Phe (i.e., blood Phe <30 µmol/L). It may be appropriate to increase blood Phe monitoring when adjusting protein intake and/or pegvaliase dose. It was recommended that natural protein intake is increased by 10-20 g increments if blood Phe concentrations decrease to <240 µmol/L in patients who are not meeting the dietary reference intake for natural protein of 0.8 g/kg. It was proposed that with pegvaliase treatment blood Phe levels could be maintained <240 µmol/L but more evidence on the safety of achieving physiological blood Phe levels is necessary before any recommendation on the lower blood Phe target can be given. Finally, both patients and dietitians should have access to educational resources to optimally support patients receiving pegvaliase. Conclusion: This practical road map aims to provide initial recommendations for dietitians monitoring patients with PKU prescribed pegvaliase. Given that practical experience with pegvaliase is still limited, nutritional recommendations will require regular updating once more evidence is available and clinical experience evolves.