Iatrogenic isolated isoleucine deficiency as the cause of an acrodermatitis enteropathica-like syndrome

Plasma amino acid concentrations during experimental hyperinsulinemia in 2 laminitis models

BACKGROUND

Endocrinopathic laminitis develops in association with insulin dysregulation, but the role of insulin in the pathogenesis remains unclear. Hyperinsulinemia can cause hypoaminoacidemia, which is associated with integumentary lesions in other species and therefore warrants investigation as a potential mechanism in laminitis.

OBJECTIVE

Evaluate plasma amino acid concentrations in the euglycemic-hyperinsulinemic clamp (EHC) and prolonged glucose infusion (PGI) laminitis models.

ANIMALS

Sixteen Standardbred horses.

METHODS

Prospective experimental study. Plasma amino acid concentrations were measured in samples collected every 6 hours from horses that underwent a 48-hour EHC (n = 8) or 66-hour PGI (n = 8) after a 24- or 6-hour baseline period in EHC and PGI groups, respectively.

RESULTS

Fifteen of the 20 measured amino acid concentrations decreased over time in both EHC and PGI horses (P < 0.001). The median percentage change from baseline for these amino acids was: histidine (EHC: 41.5%; PGI: 43.9%), glutamine (EHC: 51.8%; PGI: 35.3%), arginine (EHC: 51.4%; PGI: 41%), glutamic acid (EHC: 52.4%; PGI: 31.7%), threonine (EHC: 62.8%; PGI: 25.2%), alanine (EHC: 48.9%; PGI: 19.5%), proline (EHC: 56.2%; PGI: 30.3%), cystine (EHC: 34.9%; PGI: 31.2%), lysine (EHC: 46.4%; PGI: 27.8%), tyrosine (EHC: 27.5%; PGI: 16.9%), methionine (EHC: 69.3%; PGI: 50.8%), valine (EHC: 50.8%; PGI: 34.4%), isoleucine (EHC: 60.8%; PGI: 38.7%), leucine (EHC: 48.2%; PGI: 36.6%), and phenylalanine (EHC: 16.6%; PGI: 12.1%).

CONCLUSIONS AND CLINICAL IMPORTANCE

Hypoaminoacidemia develops in EHC and PGI laminitis models. The role of hypoaminoacidemia in the development of hyperinsulinemia-associated laminitis warrants further investigation.

Biochemical and anaplerotic applications of in vitro models of propionic acidemia and methylmalonic acidemia using patient-derived primary hepatocytes

Propionic acidemia (PA) and methylmalonic acidemia (MMA) are autosomal recessive disorders of propionyl-CoA (P-CoA) catabolism, which are caused by a deficiency in the enzyme propionyl-CoA carboxylase or the enzyme methylmalonyl-CoA (MM-CoA) mutase, respectively. The functional consequence of PA or MMA is the inability to catabolize P-CoA to MM-CoA or MM-CoA to succinyl-CoA, resulting in the accumulation of P-CoA and other metabolic intermediates, such as propionylcarnitine (C3), 3-hydroxypropionic acid, methylcitric acid (MCA), and methylmalonic acid (only in MMA). P-CoA and its metabolic intermediates, at high concentrations found in PA and MMA, inhibit enzymes in the first steps of the urea cycle as well as enzymes in the tricarboxylic acid (TCA) cycle, causing a reduction in mitochondrial energy production. We previously showed that metabolic defects of PA could be recapitulated using PA patient-derived primary hepatocytes in a novel organotypic system. Here, we sought to investigate whether treatment of normal human primary hepatocytes with propionate would recapitulate some of the biochemical features of PA and MMA in the same platform. We found that high levels of propionate resulted in high levels of intracellular P-CoA in normal hepatocytes. Analysis of TCA cycle intermediates by GC-MS/MS indicated that propionate may inhibit enzymes of the TCA cycle as shown in PA, but is also incorporated in the TCA cycle, which does not occur in PA. To better recapitulate the disease phenotype, we obtained hepatocytes derived from livers of PA and MMA patients. We characterized the PA and MMA donors by measuring key proximal biomarkers, including P-CoA, MM-CoA, as well as clinical biomarkers propionylcarnitine-to-acetylcarnitine ratios (C3/C2), MCA, and methylmalonic acid. Additionally, we used isotopically-labeled amino acids to investigate the contribution of relevant amino acids to production of P-CoA in models of metabolic stability or acute metabolic crisis. As observed clinically, we demonstrated that the isoleucine and valine catabolism pathways are the greatest sources of P-CoA in PA and MMA donor cells and that each donor showed differential sensitivity to isoleucine and valine. We also studied the effects of disodium citrate, an anaplerotic therapy, which resulted in a significant increase in the absolute concentration of TCA cycle intermediates, which is in agreement with the benefit observed clinically. Our human cell-based PA and MMA disease models can inform preclinical drug discovery and development where mouse models of these diseases are inaccurate, particularly in well-described species differences in branched-chain amino acid catabolism.

Skin Lesions Associated with Nutritional Management of Maple Syrup Urine Disease

Introduction

Maple syrup urine disease (MSUD) is an inborn error of branched chain amino acids (BCAAs) metabolism. We report an infant with MSUD who developed 2 episodes of cutaneous lesions as a result of isoleucine deficiency and zinc deficiency, respectively.

Case Presentation

A 12-day-old male infant was presented with poor milk intake and lethargy. The diagnosis of MSUD was made based on clinical and biochemical data.

Management and Outcome

Specific dietary restriction of BCAAs was given. Subsequently, natural protein was stopped as the patient developed hospital-acquired infections which resulted in an elevation of BCAAs. Acrodermatitis dysmetabolica developed and was confirmed to be from isoleucine deficiency. At the age of 6 months, the patient developed severe lethargy and was on natural protein exclusion for an extended period. Despite enteral supplementation of zinc sulfate, cutaneous manifestations due to zinc deficiency occurred.

Discussion

Skin lesions in MSUD patients could arise from multiple causes. Nutritional deficiency including isoleucine and zinc deficiencies can occur and could complicate the treatment course as a result of malabsorption, even while on enteral supplementation. Parenteral nutrition should be considered and initiated accordingly. Clinical status, as well as BCAA levels, should be closely monitored in MSUD patients.

Dietary practices in propionic acidemia: A European survey

Background

The definitive dietary management of propionic acidaemia (PA) is unknown although natural protein restriction with adequate energy provision is of key importance.

Aim

To describe European dietary practices in the management of patients with PA prior to the publication of the European PA guidelines.

Methods

This was a cross-sectional survey consisting of 27 questions about the dietary practices in PA patients circulated to European IMD dietitians and health professionals in 2014.

Results

Information on protein restricted diets of 186 PA patients from 47 centres, representing 14 European countries was collected. Total protein intake [PA precursor-free L-amino acid supplements (PFAA) and natural protein] met WHO/FAO/UNU (2007) safe protein requirements for age in 36 centres (77%). PFAA were used to supplement natural protein intake in 81% (n = 38) of centres, providing a median of 44% (14–83%) of total protein requirement. Seventy-four per cent of patients were prescribed natural protein intakes below WHO/FAO/UNU (2007) safe levels in one or more of the following age groups: 0–6 m, 7–12 m, 1–10 y, 11–16 y and > 16 y. Sixty-three per cent (n = 117) of patients were tube fed (74% gastrostomy), but only 22% received nocturnal feeds.

Conclusions

There was high use of PFAA with intakes of natural protein commonly below WHO/FAO/UNU (2007) safe levels. Optimal dietary management can only be determined by longitudinal, multi-centre, prospective case controlled studies. The metabolic instability of PA and small patient cohorts in each centre ensure that this is a challenging undertaking.

Isoleucine Deficiency in a Neonate Treated for Maple Syrup Urine Disease Masquerading as Acrodermatitis Enteropathica

BACKGROUND

Special diet with restricted branched-chain-amino-acids used for treating maple syrup urine disease can lead to specific amino acid deficiencies.

CASE CHARACTERISTICS

We report a neonate who developed skin lesions due to isoleucine deficiency while using specialised formula.

INTERVENTION/OUTCOME

Feeds were supplemented with expressed breast milk. This caused biochemical and clinical improvement with resolution of skin lesions.

MESSAGE

Breast milk is a valuable and necessary adjunct to specialized formula in maple syrup urine disease to prevent specific amino acid deficiency in the neonatal period.

Single amino acid supplementation in aminoacidopathies: a systematic review

Aminoacidopathies are a group of rare and diverse disorders, caused by the deficiency of an enzyme or transporter involved in amino acid metabolism. For most aminoacidopathies, dietary management is the mainstay of treatment. Such treatment includes severe natural protein restriction, combined with protein substitution with all amino acids except the amino acids prior to the metabolic block and enriched with the amino acid that has become essential by the enzymatic defect. For some aminoacidopathies, supplementation of one or two amino acids, that have not become essential by the enzymatic defect, has been suggested. This so-called single amino acid supplementation can serve different treatment objectives, but evidence is limited. The aim of the present article is to provide a systematic review on the reasons for applications of single amino acid supplementation in aminoacidopathies treated with natural protein restriction and synthetic amino acid mixtures.

Docosahexaenoic acid status in females of reproductive age with maple syrup urine disease

Individuals with maple syrup urine disease (MSUD) have impaired metabolism of branched-chain amino acids (BCAA) valine, isoleucine, and leucine. Life-long dietary therapy is recommended to restrict BCAA intake and thus prevent poor neurological outcomes and death. To maintain adequate nutritional status, the majority of protein and nutrients are derived from synthetic BCAA-free medical foods with variable fatty acid content. Given the restrictive diet and the importance of omega-3 fatty acids, particularly docosahexaenoic acid (DHA), in neurological development, this study evaluated the dietary and fatty acid status of females of reproductive age with MSUD attending a metabolic camp. Healthy controls of similar age and sex were selected from existing normal laboratory data. Total lipid fatty acid concentration in plasma and erythrocytes was analyzed using gas chromatography-mass spectroscopy. Participants with MSUD had normal to increased concentrations of plasma and erythrocyte alpha linolenic acid (ALA) but significantly lower concentrations of plasma and erythrocyte docosahexaenoic acid (DHA) as percent of total lipid fatty acids compared with controls (plasma DHA: MSUD 1.03 +/- 0.35, controls 2.87 +/- 1.08; P = 0.001; erythrocyte DHA: MSUD 2.58 +/- 0.58, controls 3.66 +/- 0.80; P = 0.011). Dietary records reflected negligible or no DHA intake over the 3-day period prior to the blood draw (range 0-2 mg). These results suggest females of reproductive age with MSUD have lower blood DHA concentrations than age-matched controls. In addition, the presence of ALA in medical foods and the background diet may not counter the lack of preformed DHA in the diet. The implications of these results warrant further investigation.

Changes in plasma amino acid concentrations with increasing age in patients with propionic acidemia

The objective of the study is to analyze plasma amino acid concentrations in propionic acidemia (PA) for the purpose of elucidating possible correlations between propionyl-CoA carboxylase deficiency and distinct amino acid behavior. Plasma concentrations of 19 amino acids were measured in 240 random samples from 11 patients (6 families) with enzymatically and/or genetically proven propionic acidemia (sampling period, January 2001-December 2007). They were compared with reference values from the literature and correlated with age using the Pearson correlation coefficient test. Decreased plasma concentrations were observed for glutamine, histidine, threonine, valine, isoleucine, leucine, phenylalanine and arginine. Levels of glycine, alanine and aspartate were elevated, while values of serine, asparagine, ornithine and glutamate were normal. For lysine, proline and methionine a clear association was not possible. Significant correlations with age were observed for 13 amino acids (positive correlation: asparagine, glutamine, proline, alanine, histidine, threonine, methionine, arginine; negative correlation: leucine, phenylalanine, ornithine, glutamate and aspartate). This study gives new insight over long-term changes in plasma amino acid concentrations and may provide options for future therapies (e.g., substitution of anaplerotic substances) in PA patients.

Acrodermatitis enteropathica-like eruption in metabolic disorders: acrodermatitis dysmetabolica is proposed as a better term

BACKGROUND

Acrodermatitis acidemica is a recently proposed term for the rash that is similar to acrodermatitis enteropathica, which is encountered in organic acidemias. However, acrodermatitis enteropathica-like eruption may be seen in metabolic disorders other than organic acidemias.

OBJECTIVE

The aim of this study was to evaluate the clinical features of acrodermatitis enteropathica-like eruption secondary to metabolic disorders.

METHODS

Clinical and demographic features of 12 patients with acrodermatitis enteropathica-like eruption were prospectively evaluated between 2004 and 2006 in this single-center study.

RESULTS

Among the 12 patients, underlying metabolic disorders included maple syrup urine disease (n = 5), methylmalonic acidemia (n = 3), phenylketonuria (n = 2), ornithine transcarbamylase deficiency (n = 1), and propionic acidemia (n = 1). Mean age at first presentation was 29.9 months. Mean duration of acrodermatitis enteropathica-like eruption at the time of presentation was 25.2 days. The diaper area was involved in all presentations. Plasma zinc level was measured in 62.5% (n = 10) of the presentations and all had normal levels. All phenylketonuria cases had a low plasma phenylalanine level, and a low plasma isoleucine level was observed in the propionic acidemia case and all maple syrup urine disease cases. The rash responded dramatically to appropriate diet management in all cases.

CONCLUSION

In this study, acrodermatitis enteropathica-like eruption was noted in various metabolic disorders, including organic acidemias. We suggest that acrodermatitis dysmetabolica might be a better term for acrodermatitis enteropathica-like eruption occurring secondary to metabolic disorders other than acquired zinc deficiency.

Acrodermatitis enteropathica–like eruption and failure to thrive as presenting signs of cystic fibrosis

We describe a female infant with an acrodermatitis enteropathica-like eruption as the presenting sign of rapidly fatal cystic fibrosis. The patient had growth retardation, developed an erythematous eruption unresponsive to oral zinc, and finally a generalized erosive dermatitis with associated edema, anemia and hypoproteinemia.

Lesões de pele do tipo acrodermatite enteropática em duas crianças com doença da urina de xarope do bordo

Lesões cutâneas semelhantes à acrodermatite enteropática têm sido descritas em pacientes com algumas doenças metabólicas tratadas com dietas hipoprotéicas. Esses pacientes geralmente apresentam baixos níveis séricos de alguns aminoácidos, especialmente da isoleucina. Descrevemos dois pacientes que evoluíram com lesões semelhantes às da acrodermatite enteropática durante o tratamento da doença da urina do xarope de bordo , sem deficiência do zinco. A suplementação da isoleucina determinou rápida melhora das lesões dermatológicas.

Acrodermatitis enteropathica-like eruptions in a child with Hartnup disease

Acrodermatitis enteropathica-like eruptions, not related to zinc deficiency, have been rarely reported in some metabolic disorders. Reported patients usually had low levels of essential amino acids, particularly isoleucine. Here we report a girl who first presented with an acrodermatitis enteropathica-like eruption and eventually had the diagnosis of Hartnup disease with a normal isoleucine level. We discuss the probable cause of her skin lesions and the differential diagnosis with pellagra.

Pseudo-acrodermatite entéropathique secondaire à un déficit en acides aminés ramifiés au cours du traitement d’une leucinose

INTRODUCTION

Clinical pictures resembling acrodermatitis enteropathica have been described in acquired zinc deficiency and deficiencies of other nutrients such as biotin, essential fatty acids and amino acids as well as biotin metabolism disorders. We describe the case of an infant with maple syrup urine disease who developed an acrodermatitis-like syndrome due to iatrogenic valine and isoleucine deficiency.

CASE-REPORT

A diagnosis of maple syrup urine disease was made in a 5-month-old infant girl with severe neurologic disorders with extremely high levels of the three branched-chain amino acids (leucine, valine and isoleucine) in plasma and urine. Seven days after the start of therapy with a diet excluding these branched-chain amino acids, plasma isoleucine and valine concentrations were low while plasma leucine remained elevated. At the same time, a periorificial and acral dermatitis appeared together with diarrhea. Serum zinc concentrations were normal. A diagnosis of acrodermatitis enteropathica-like syndrome secondary to isoleucine and valine deficiency was suspected. Valine and isoleucine supplementation resulted in rapid resolution of the eruption.

DISCUSSION

Several cases of acrodermatitis enteropathica-like eruptions resulting from therapeutic protein restriction diets have been described in infants with different aminoacidopathies. The accompanying dermatosis was associated with a raised plasma leucine/isoleucine ratio and/or isoleucine deficiency, or valine deficiency. While the exact pathogenesis of the skin lesions has not been established, these observations show that branched-chain amino acids are essential for normal growth and differentiation of keratinocytes. The essential role of isoleucine is further substantiated by the fact that its presence is critical in keratinocyte culture media, with growth arrest occurring upon its depletion.

Pseudo-acrodermatite entéropathique par carence alimentaire en isoleucine chez un nourrisson atteint de leucinose

INTRODUCTION

Leucinosis (maple syrup urine disease) is a metabolic disorder caused by an enzymatic deficiency involved in the degradative pathways of the three branched-chain amino acids. We report an observation of acrodermatitis enteropathica-like syndrome induced by essential amino acid deficiency in a child with leucinosis.

CASE REPORT

A child with leucinosis was referred to our hospital for exfoliative dermatitis of the perioral and anogenital regions associated with diarrhea and pancytopenia. The diagnosis of iatrogenic acrodermatitis enteropathica-like syndrome was confirmed after screening showing isoleucine deficiency. Rapid response was observed after adequate isoleucine supplementation.

DISCUSSION

The acrodermatitis enteropathica-like eruption in our patient was due to an iatrogenic amino acid nutritional imbalance. Our observation underlines the risk of using a branched-chain amino acid-free formula without adequate supplementation of deficient amino acids. In addition, dietary insufficiency of isoleucine, associated with the treatment of organic aciduria should be added to the causes of acrodermatitis enteropathica-like syndrome.

Acrodermatitis enteropathica: case report and review of the literature

Acrodermatitis enteropathica (AE) is a rare hereditary disorder caused by impaired absorption of zinc from the gastrointestinal tract. It is characterized by acral and periorificial dermatitis, alopecia, and diarrhea. Symptoms usually begin on weaning from breast or formula feeding. We report a full-term, 21-month-old boy with typical skin lesions and decreased plasma zinc level (12 micro g/dl). The patient was given zinc sulfate 40 mg/day and at the end of 1 month his condition had improved significantly. After reviewing the literature we emphasize the important role of zinc in human metabolism and the difference between AE and acquired zinc deficiencies.

Long-term treatment with sodium phenylbutyrate in ornithine transcarbamylase-deficient patients

Ornithine transcarbamylase deficiency is a very heterogeneous urea cycle disorder resulting in hyperammonemia with various presentations from the neonatal period through adulthood. We performed a retrospective study in nine patients (four male/five female, age at diagnosis ranging from 6 days to 14 years) to evaluate the safety and efficacy of sodium phenylbutyrate (Ammonaps) in long-term treatment. All patients were diagnosed by DNA mutational analysis and/or liver enzyme measurement. They had previously been treated with sodium benzoate (median dose 248 mg/kg/day; range 106-275) and low protein diet (median 0.84 g/kg/day) and were switched to sodium phenylbutyrate (median dose of 352 mg/kg/day) at 8.9 and 4.9 years of age (median) in males and females, respectively. We analyzed clinical and biochemical data and the median follow-up duration was 26 months. During that time, there were no hyperammonemic episodes requiring hospitalization. Median plasma ammonia and glutamine levels were 30 and 902 micromol/L, respectively. Total protein intake could be increased to 0.95 g/kg/day after 18 months. No side effects related to therapy were observed. Further prospective studies should be performed to define the optimal dosage of sodium phenylbutyrate and the requirements for protein diet at different ages.