Diagnostic accuracy and the first genotype-phenotype correlation in glycogen storage disease type V.

BACKGROUND: Glycogen storage disease type V (GSDV) is an autosomal recessive metabolic condition caused by pathogenic PYGM variants. This is an underdiagnosed condition as it presents with exercise intolerance in children. We reviewed the GSDV cases of a tertiary hospital center to assess diagnostic timing/accuracy, as well as potential clinical/analytical predictors of such factors. METHODS: We retrospectively reviewed all GSDV cases with follow-up in both Pediatric and Adult Metabolic Diseases consultations. We included 28 cases and assessed their hospital record for clinical information. RESULTS: Over 90% of our cases had late diagnoses, with more than 50% being diagnosed in adulthood despite symptom onset in preschool (very late diagnosis). Diagnostic age was lower in patients exhibiting myoglobinuria. Interestingly, patients with a positive family history of GSDV had similar rates of very late diagnoses, likely since the index case was already detected very late in life. Finally, we observe that the R50* variant is associated with increased myoglobinuria and CK elevation, in a dosage-dependent manner. CONCLUSION: We concluded that GSDV is severely underdiagnosed, and that some clinical and analytical aspects of the condition can be more indicative of this diagnosis. Furthermore, we propose for the first time a genotype-phenotype correlation in GSDV. IMPACT: GSDV is a pediatric-onset metabolic disorder that is mostly diagnosed late in the adult age and commonly misdiagnosed. We observed the first genotype-phenotype correlation in GSDV, regarding the common R50* variant. Awareness of GSDV for pediatricians and the overall medical community is vital.

Clinical and Laboratory Findings on Glycogen Storage Disease Type V: Results from a Retrospective Observational Study in a Tertiary Hospital.

Introduction - Glycogen storage disease type V (GSDV, MIM #232600) is an autosomal recessive metabolic myopathy caused by pathogenic variants in the PYGM gene. The characteristic symptoms of exercise intolerance, myalgia, and cramps, which improve after a few minutes of rest, are frequently unrecognized in affected children. When there is clinical suspicion, the initial approach with a forearm exercise test has diagnostic value by detecting low post-exercise plasma lactate-to-ammonia ratio values. The diagnostic algorithm is followed by genetic testing if the results suggest myophosphorylase deficiency. Methods - This was a retrospective observational study conducted based on reviewing medical records of patients with GSDV in a tertiary hospital. We assessed demographic variables, including the timing of onset and diagnosis, relevant clinical characteristics, and whether genetic testing was performed, including its results. Results/Case Report - Our goal was to review the GSDV cases in our center to assess our cohort's diagnostic timing and clinical and genetic characteristics. We identified 28 patients from 24 families, three with consanguinity. The mean age at the time of the study was 43 years. While most (26/28; 93%) recalled their first symptoms in childhood/adolescence, only 25% (7/28) were diagnosed then. All patients had exercise intolerance and CK elevation, while about half reported the second wind phenomenon. Genetic testing was performed in 22 patients, revealing biallelic PYGM variants (9 homozygous, 13 compound heterozygous) as the most common (p.R50*). Conclusion - GSDV is rare and presents in the pediatric age, with subtle manifestations often underestimated for decades. A late diagnosis may negatively impact the psychosocial development of affected children. It is essential to recognize some unique features that facilitate diagnosis: history of exercise intolerance, the second wind sign, and high resting serum CK levels. Identifying the disease-causing variants in PYGM is currently the gold standard for diagnosis as it is less invasive than performing a muscle biopsy, and may promptly diagnose the condition and avoid wrongful labelling of patients.

From recurrent rhabdomyolysis in a young adult to carnitine palmitoyltransferase II deficiency.

Metabolic myopathies are a diverse group of rare genetic disorders associated with recurrent episodes of rhabdomyolysis, induced by triggers such as fever or exercise. In these disorders, the energetic metabolism is compromised resulting in damage of the muscle cells. The diagnosis can be challenging but is essential for the correct treatment. Carnitine palmitoytransferase II (CPT-II) deficiency is the most common long-chain fatty acid oxidation defect, with the adulthood form requiring additional external triggers. The authors present a case of a young-male adult with recurrent episodes of rhabdomyolysis, one of them presented with acute renal failure and acute hepatitis. The diagnostic is demanding, which requires a high level of suspicion. The adequate treatment of these patients improves the muscle function and prevents other episodes of severe rhabdomyolysis.

Glutaric Aciduria Type 2 Presenting in Adult Life With Hypoglycemia and Encephalopathic Hyperammonemia.

Glutaric aciduria type 2 is a rare inborn disease of fatty acid metabolism. The clinical manifestation of this disease is heterogeneous and ranges from severe neonatal forms to mild late-onset forms. We present a case of a previously healthy 22-year-old woman with unexplainable hypoglycemia and encephalopathic hyperammonemia. Acylcarnitine profile and organic acids analysis were compatible with glutaric aciduria type 2. On suspicion of this disease, the patient started supplements with carnitine and riboflavin, along with hemodialysis with a complete recovery. The genetic test confirmed the diagnosis. Glutaric aciduria type 2 has no cure and the metabolic decompensation can be a severe event, but treatable and preventable, if this pathology gets recognized.

Hunter Syndrome: The Phenotype of a Rare Storage Disease.

Hunter syndrome is a rare lysosomal storage disorder with systemic involvement that occurs over time. Affected patients have coarse facial features, growth retardation with short stature, and skeletal deformities called dysostosis multiplex; joint stiffness, progressive mental retardation, and organomegaly are some of the clinical signs. It ranges from mild to severe manifestations and the distinction between them is related to neurological involvement. Cardiac and respiratory failure is commonly the cause of early death (before adulthood) for severe forms, but those with attenuated forms who have normal cognitive development can survive until late adulthood. Treatment with enzyme replacement therapy is available and can improve the prognosis of this disease. The authors present a case of a 36-year-old male with Hunter syndrome to show not only the clinical features typical of this multisystemic disease that should alert to a prompt investigation but also to remind that treatment must start as early as possible to reach the best outcome. Management of this disease is typically challenging and requires a multidisciplinary approach.

Niemann-Pick Type B: A Rare Cause of Interstitial Lung Disease.

Niemann-Pick disease (NPD) is a rare lysosomal storage disease (LSD) with multisystemic involvement. The disease is heterogeneous and classified into three subtypes: type A and B result from deficient acid sphingomyelinase activity and leads to the accumulation of sphingomyelin and type C is a genetically different disease resulting from defective intracellular trafficking of cholesterol with accumulation of glycosphingolipids. Type A is generally a neurodegenerative disease and is fatal in infancy. Type B is a less severe form characterized by pulmonary involvement, hepatosplenomegaly, hyperlipidemia and most patients live into adulthood. In type C, clinical presentation is dominated with neurological involvement. Pulmonary involvement occurs in all three types of Niemann-Pick but most frequently in type B. Clinical manifestations range from a lack of symptoms to respiratory failure, and respiratory symptoms are usually mild with recurrent cough, dyspnoea on exertion and recurrent respiratory infections. Interstitial lung disease (ILD) is the most prominent feature with slow progression, characterized by worsening pulmonary function tests. In recent years, enzyme replacement therapy has shown promising results in clinical trials, such as improvement in organomegaly and pulmonary involvement with the potential to improve patients' lives. We present three cases of NPD with pulmonary involvement, each exhibiting a different pattern of ILD and evaluate therapeutic options.

Metabolic Control of Patients with Phenylketonuria in a Portuguese Metabolic Centre Comparing Three Different Recommendations.

Blood phenylalanine (Phe) is used as the primary marker to evaluate metabolic control. Our study aimed to describe the metabolic control of patients with phenylketonuria (PKU) comparing three different treatment recommendations (European guidelines/US guidelines/Portuguese consensus). This was a retrospective, observational, single centre study in patients with PKU collecting data on blood Phe levels from 2017. Nutritional intake data and sapropterin (BH4) prescription were collected at the last appointment of 2017. The final sample studied included 87 patients (48% females) [13 hyperphenylalaninemia; 47 mild PKU; 27 classical PKU] with a median age of 18 y (range: 1-36 y). The median number of blood Phe measurements for patients was 21 (range: 6-89). In patients aged < 12 y, the median blood Phe level was 300 µmol/L (range 168-480) and 474 µmol/L (range 156-1194) for patients ≥ 12 y. Overall, a median of 83% of blood Phe levels were within the European PKU guidelines target range. In patients aged ≥ 12 years, there was a higher median % of blood Phe levels within the European PKU guidelines target range (≥12 y: 84% vs. <12 y: 56%). In children < 12 y with classical PKU (n = 2), only 34% of blood Phe levels were within target range for all 3 guidelines and 49% with mild PKU (n = 11). Girls had better control than boys (89% vs. 66% median Phe levels within European Guidelines). Although it is clear that 50% or more patients were unable to achieve acceptable metabolic control on current treatment options, a globally agreed upper Phe target associated with optimal outcomes for age groups is necessary. More studies need to examine how clinics with dissimilar resources, different therapeutic Phe targets and frequency of monitoring relate to metabolic control.

The Role of a Medical Intermediate Care Unit in the Management of Budd-Chiari Syndrome: Case Series.

Budd-Chiari syndrome (BCS) has a wide spectrum of presentations, from an asymptomatic status to acute liver failure (ALF). The therapeutic approach depends on disease severity and related etiology with patients with severe forms of presentation classically managed in intensive care units (ICUs). Here, we report a series of five BCS patients managed in a medical intermediate care unit (IntCU), with three of them presenting with acute liver injury. Progression to ALF was seen in three patients, two of whom died, with one being successfully submitted to liver transplantation. IntCUs allow a 24-h patient surveillance and a prompt management of BCS, with less economic impact when compared to ICUs. Mortality was related to the presence of associated comorbidities that limited therapeutic approach.

Implementing a Transition Program from Paediatric to Adult Services in Phenylketonuria: Results After Two Years of Follow-Up with an Adult Team.

We aimed to report the implementation of a phenylketonuria (PKU) transition program and study the effects of follow-up with an adult team on metabolic control, adherence, and loss of follow-up. Fifty-five PKU patients were analysed in the study periods (SP): 2 years before (SP1) and after the beginning of adult care (SP2). Retrospective data on metabolic control and number of clinic appointments were collected for each SP, and protein intakes were analysed. In SP2, three patients (6%) were lost to follow-up. There was a small but statistically significant increase in median number of annual blood spots from SP1 to SP2: 11 (7-15) vs. 14 (7-20); p = 0.002. Mean ± SD of median blood Phe remained stable (525 ± 248 µmol/L vs. 552 ± 225 µmol/L; p = 0.100); median % of blood Phe < 480 µmol/L decreased (51 (4-96)% vs. 37 (5-85)%; p = 0.041) and median number of clinic appointments increased from SP1 to SP2: (5 (4-6) vs. 11 (8-13); p < 0.001). No significant differences were found regarding any parameter of protein intake. Our results suggest that the implementation of an adult service was successful as impact on metabolic control was limited and attendance remained high. Continuous dietetic care likely contributed to these results by keeping patients in follow-up and committed to treatment.

Continuous use of glycomacropeptide in the nutritional management of patients with phenylketonuria: a clinical perspective.

BACKGROUND: In phenylketonuria (PKU), modified casein glycomacropeptide supplements (CGMP-AA) are used as an alternative to the traditional phenylalanine (Phe)-free L-amino acid supplements (L-AA). However, studies focusing on the long-term nutritional status of CGMP-AA are lacking. This retrospective study evaluated the long-term impact of CGMP-AA over a mean of 29 months in 11 patients with a mean age at CGMP-AA onset of 28 years (range 15-43) [8 females; 2 hyperphenylalaninaemia (HPA), 3 mild PKU, 3 classical PKU and 3 late-diagnosed]. Outcome measures included metabolic control, anthropometry, body composition and biochemical parameters. RESULTS: CGMP-AA, providing 66% of protein equivalent intake from protein substitute, was associated with no significant change in blood Phe with CGMP-AA compared with baseline (562 ± 289 µmol/L vs 628 ± 317 µmol/L; p = 0.065). In contrast, blood tyrosine significantly increased on CGMP-AA (52.0 ± 19.2 µmol/L vs 61.4 ± 23.8 µmol/L; p = 0.027). CONCLUSIONS: Biochemical nutritional markers remained unchanged which is an encouraging finding in adults with PKU, many of whom are unable to maintain full adherence with nutritionally fortified protein substitutes. Longitudinal, prospective studies with larger sample sizes are necessary to fully understand the metabolic impact of using CGMP-AA in PKU.

Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria.

Phenylalanine (Phe) tolerance is highly variable in phenylketonuria (PKU) and rarely described in patients aged ≥12 years. Patients ≥12 years of age with PKU were systematically challenged with additional natural protein (NP) if blood Phe levels remained below 480 µmol/L (i.e., upper target blood Phe level for patients aged ≥12 years using Portuguese PKU guidelines). In PKU patients, NP tolerance was calculated at baseline and a median of 6 months after systematic challenge with NP whilst patients were maintaining a blood Phe ≤480 µmol/L. Anthropometry was assessed at both times. Routine blood Phe levels were collected. We studied 40 well-controlled PKU patients (10 hyperphenylalaninemia (HPA), 23 mild and 7 classic PKU), on a low-Phe diet with a mean age of 17 years (12-29 years). Median daily NP intake significantly increased between assessments (35 vs. 40 g/day, p = 0.01). Twenty-six patients (65%) were able to increase their median NP intake by a median 12 g/day (2-42 g)/day and still maintain blood Phe within target range. Out of the previous 26 patients, 20 (77%) (8 HPA, 11 mild and 1 classical PKU) increased NP from animal sources (e.g. dairy products, fish and meat) and 6 patients (23%) (3 mild and 3 classical PKU) from plant foods (bread, pasta, potatoes). Median protein equivalent intake from Phe-free/low-Phe protein substitute decreased (0.82 vs. 0.75 g/kg, p = 0.01), while median blood Phe levels remained unchanged (279 vs. 288 µmol/L, p = 0.06). Almost two-thirds of patients with PKU tolerated additional NP when challenged and still maintained blood Phe within the national target range. This suggests that some patients with PKU treated by a low-Phe diet only may over restrict their NP intake. In order to minimise the burden of treatment and optimise NP intake, it is important to challenge with additional NP at periodic intervals.

Metabolic Control in Patients With Phenylketonuria Pre- and Post-Sapropterin Loading Test

Abstract In Portugal, tetrahydrobiopterin (BH4)-responsive patients with phenylketonuria (PKU) are identified using a loading test (LT). Phenylalanine/natural protein (Phe/NP) intake is increased to elevate blood Phe prior to the LT. In a longitudinal retrospective study, the impact of Phe/NP titration post-LT in 58 patients (19.6 + 8.2 years) with PKU during 4 study periods (SPs) was examined. In SP1 (2010-2013), patients were diet treated only; in SP2 (2014), the Phe/NP titration was followed by the LT in SP3 (2015). In SP4 (2016), patients received diet treatment only (n » 49) or BH4 þdiet (n » 9). The median percentage blood Phe within the target range was higher in SP1 versus SP4 (64 [28-85] vs 45 [0-66]; P < .001). Our results suggest that transient Phe/NP titration, associated with a deliberate increase in NP, may adversely affect metabolic control. Controlled studies are necessary to examine the longer term impact of temporary increased NP with BH4 LT in non-BH4-responsive patients.

[Mediterranean Spotted Fever: Retrospective Review of Hospitalized Cases and Predictive Factors of Severe Disease]. / Febre Escaro-Nodular: Revisão Retrospetiva de Casos Hospitalizados e Fatores Preditores de Doença Severa.

INTRODUCTION: Mediterranean spotted fever, an ancient zoonotic disease raising current issues. This study aims to reevaluate the disease clinical picture and to identify prognostic factors related to severe disease. MATERIAL AND METHODS: We evaluate cases admitted to a central hospital during 12-year period. The risk factors were determined by uni and multivariate analysis, comparing patients admitted in general infirmary versus intermediate/intensive care units or in case of death. RESULTS: We reviewed 71 cases of Mediterranean spotted fever. The mean age was 63.3 ± 16.7 years and 52.1% were male. The eschar was observed in 62.0%. Fever and rash were the most common clinical findings. Forty five percent of patients developed complications and 22.5% were admitted to intermediate and/or intensive care units. Apyrexia, dyspnea, renal failure and elevated lactic dehydrogenase levels at admission were predictors of severe disease development (p < 0.034). Alcoholism was related with prolonged hospitalization (p = 0.020). Absence of fever (p = 0.019) and elevated serum creatinine levels (p = 0.028) were identified as independent factors associated with severe outcome. The mortality rate was 2.8%. DISCUSSION: Although Mediterranean spotted fever is usually assumed to be benign, severe cases are emerging. CONCLUSION: Early identification of the infection and continuous patient surveillance are crucial, particularly in those with greater risk of developing severe or fatal disease.

Introdução: Febre escaro-nodular, uma zoonose antiga a levantar questões actuais. Este estudo pretende reavaliar a imagem clínica da doença e identificar factores prognósticos de doença severa. Material e Métodos: Foram avaliados os casos admitidos num hospital central no período de 12 anos. Os fatores de risco foram determinados por análise uni e multivariada, comparando os indivíduos internados em enfermaria geral versus admitidos em unidades de cuidados intermédios/intensivos ou em caso de morte. Resultados: Foram revistos 71 casos de febre escaro-nodular. A média de idades foi 63,3 ± 16,7 anos e 52,1% eram homens. A escara de inoculação foi identificada em 62,0% dos casos. Febre e exantema foram os achados clínicos mais frequentes. Quarenta e cinco por cento dos doentes desenvolveram complicações e 22,5% foram internados em unidades de cuidados intermédios e/ou intensivos. Apirexia, dispneia, insuficiência renal e níveis de lactato desidrogenase elevados à admissão foram preditores de desenvolvimentode doença severa (p < 0,034). O alcoolismo associou-se a um tempo de internamento prolongado (p = 0,020). Ausênciade febre (p = 0,019) e níveis elevados de creatinina (p = 0,028) constituíram fatores independentes de mau prognóstico. A taxa de mortalidade foi 2,8%.Discussão: Apesar da evolução da febre escaro-nodular ser, geralmente, assumida como benigna, casos graves têm surgido. Quase metade dos doentes hospitalizados desenvolveu complicações. Apirexia e lesão renal predispõem a pior prognóstico. Conclusão: A identificação precoce da infeção e a vigilância contínua dos doentes são determinantes, particularmente naqueles com maior risco de desenvolverem doença severa ou fatal.

Diffuse plane xanthomatosis associated with monoclonal gammopathy.

Diffuse plane normolipemic xanthomatosis (DPNX) is a rare, non-inherited disease that is often associated with systemic diseases, mainly malignant hematological (especially multiple myeloma) or lymph proliferative disorders. The DPNX can precede the appearance of such conditions by several years, so careful follow-up and periodic laboratory examinations are recommended even for patients that seemed to have no underlying disease. We describe a case associated with monoclonal gammopathy. This case shows that dermatological lesions can be the first manifestation of important hematological diseases and so physicians should be familiarized with this entity.

Diffuse plane xanthomatosis associated with monoclonal gammopathy / Xantomatose plana difusa associada a gamopatia monoclonal

Diffuse plane normolipemic xanthomatosis (DPNX) is a rare, non-inherited disease that is often associated with systemic diseases, mainly malignant hematological (especially multiple myeloma) or lymph proliferative disorders. The DPNX can precede the appearance of such conditions by several years, so careful follow-up and periodic laboratory examinations are recommended even for patients that seemed to have no underlying disease. We describe a case associated with monoclonal gammopathy. This case shows that dermatological lesions can be the first manifestation of important hematological diseases and so physicians should be familiarized with this entity.

A xantomatose plana difusa normolipêmica (XPDN) é uma dermatose adquirida rara, muitas vezes associada a doenças sistêmicas, nomeadamente neoplasias hematológicas(sobretudo o mieloma múltiplo) ou a processos linfoproliferativos. A XPDN pode preceder o aparecimento dessas doenças em vários anos, sendo por isso recomendada uma vigilância clínica e laboratorial periódica, mesmo para os doentes que aparentemente não apresentam uma doença associada. Descrevemos um caso associado à gamopatia monoclonal. Este caso demonstra a importância das manifestações cutâneas como primeira manifestação de doenças hematológicas importantes e por isso os clínicos devem estar familiarizados com esta entidade.