Special low protein foods for phenylketonuria in Turkey: An examination of their nutritional composition compared to regular food.

Background: Special low protein foods (SLPF) that are phenylalanine (Phe)-free or have a low Phe content are an integral part of PKU diet therapy. Aim: The aim of this study is to determine the nutritional profiles of SLPFs used in Turkey and to compare their contents with equivalent products in the "regular" category, in order to evaluate nutritional and metabolic risks. Methods: Between February and March 2022, the information concerning the nutritional contents of "special low protein products" recommended for PKU and available in Turkey were obtained from the websites of producers/suppliers. Results: A total of 148 SLPFs were identified in Turkey. Compared to regular products, SLPFs were determined to contain less sugar and high carbohydrate content in the Turkish market (p < 0.001). Overall, SLPF products had higher dietary fiber compared to products with regular protein content (p < 0.001). In SLPF subgroups, meat substitutes, rice and pasta, and soup products had significantly less total fat than regular products; low protein bread, sweet snacks, and salted crackers were found to contain less saturated fat (p < 0.05). Moreover, all SLPFs contained significantly more salt than regular products, especially the salt content of subgroups of low protein bread, flour, pasta, and rice was significantly higher than regular products (p < 0.05). Conclusion: Including detailed nutritional information on the Turkish SLPFs' food labels will be effective for patients with PKU to follow themselves on their own.

Cardiologic evaluation of Turkish mitochondrial fatty acid oxidation disorders.

BACKGROUND: Mitochondrial fatty acid oxidation disorders (FAODs) cause impairment in energy metabolism and can lead to a spectrum of cardiac pathologies including cardiomyopathy and arrhythmias. The frequency of underlying cardiac pathologies and the response to recommended treatment in FAODs was investigated. METHODS: Sixty-eight children (35 males, 33 females) with the diagnosis of a FAOD were included in the study. Cardiac function was evaluated with 12-lead standard electrocardiography, echocardiography, and 24 h Holter monitoring. RESULTS: Forty-five patients (66%) were diagnosed after disease symptoms developed and 23 patients (34%) were diagnosed in the pre-symptomatic period. Among symptomatic patients (n: 45), cardiovascular findings were detected in 18 (40%) patients, including cardiomyopathy in 14 (31.1%) and conduction abnormalities in 4 (8.8%) patients. Cardiac symptoms were more frequently detected in primary systemic carnitine deficiency (57.1%). Patients with multiple acyl-CoA dehydrogenase, long-chain 3-hydroxyacyl-CoA dehydrogenase, and mitochondrial trifunctional protein deficiencies also had an increased frequency of cardiac symptoms. Patients with medium-chain acyl-CoA dehydrogenase, very long-chain acyl-CoA dehydrogenase, and carnitine palmitoyltransferase I deficiencies had a lower prevalence of cardiac symptoms both during admission and during clinical follow up. Cardiomyopathy resolved completely in 8/14 (57%) patients and partially in 2/14 (14.3%) patients with treatment. Two patients with cardiomyopathy died in the newborn period; cardiomyopathy persisted in 1 (7.1%) patient with very long-chain acyl-CoA dehydrogenase deficiency. CONCLUSION: Early diagnosis, treatment and follow up made a significant contribution to the improvement of cardiac symptoms of patients with FAODs.

A different perspective into clinical symptoms in CPT I deficiency.

Carnitine palmitoyltransferase I (CPT I) deficiency is an autosomal recessive disorder causing long-chain fatty acid oxidation defect, characterized by metabolic decompensation episodes accompanied by hypoketotic hypoglycemia, hepatomegaly, seizures, renal tubular acidosis, and hyperammonemia. The aim of this study was to investigate the neurological symptoms in CPT I deficiency and different outcomes with respect to predisposing factors for sequela and to draw attention to the neurological impairment that may develop during the course of the disease. The retrospective study reviewed clinical characteristics of 14 patients. Mean follow-up period was 10.3 ± 4.7 (range: 8 months-18.6 years; median: 10 years) years. Three patients were diagnosed with newborn screening. In the symptomatic group (n = 12) most common presenting symptoms were psychomotor retardation (n = 6), seizures (n = 5), encephalopathy (n = 5), dystonia (n = 1), Reye-like syndrome (n = 5), muscle weakness (n = 3), and autism (n = 1). Neurologic findings detected in the follow-up period included speech disorder (n = 9), abnormal cranial MRI findings (n = 5), neuropathy (n = 1), and attention deficit hyperactivity disorder (n = 1). Speech disorders collectively included delayed expressive language development, speech articulation disorder, speech delay, stuttering, and specific speech difficulties. After starting treatment for CPT I deficiency, speech disorders improved in 3 patients. Our findings confirmed that the clinical manifestations of CPT I deficiency is wider than previously thought, causing specific neurologic dysfunction, mainly speech disorders at a large scale, that were unexpected in a fatty acid oxidation disorder. We suggest that early diagnosis and treatment is the key factor to prevent neurologic sequelae while an extensive neurological evaluation is essential in patients with CPT I deficiency both at the time of diagnosis and during the follow-up period.

Leucine tolerance in children with MSUD is not correlated with plasma leucine levels at diagnosis.

OBJECTIVES: Maple syrup urine disease (MSUD) is an inborn metabolic disease. The nutritional treatment with restricted intake of branched chain amino acids and prevention of leucine toxicity are crucially important for a favorable outcome. The aim of this study is to analyze the relation of blood leucine levels at diagnosis with future leucine tolerances, to determine whether any prediction about the future leucine tolerances or plasma leucine levels is possible by evaluating blood leucine levels at diagnosis. METHODS: The study group consisted of 45 MSUD patients. Leucine levels at diagnosis were compared with age at diagnosis, leucine tolerances, maximum leucine levels/ages, and average blood leucine levels. RESULTS: The mean plasma leucine level at diagnosis was 2,355.47 ± 1,251.7 µmol/L (ref: 55-164 µmol/L). The median age at diagnosis was 17 days. Leucine tolerances per kg body weight declined until the age of 8 years and stabilized subsequently. The average age of maximum leucine level during follow-up was 3.14 ± 1.92 years, and the mean maximum lifetime plasma leucine level on follow-up was 1,452.13 ± 621.38 µmol/L. The leucine levels at diagnosis did not have any significant relationship with lifetime leucine tolerances, maximum plasma leucine levels or mean plasma leucine levels. CONCLUSIONS: The plasma leucine levels at diagnosis did not have a predictive value for later leucine tolerances or plasma leucine levels. The maximum lifetime leucine level is likely to happen within the first 3 years of life, underlining the importance of good metabolic control and compliance to dietary treatment at early ages.

Expert opinion on patient journey, diagnosis and clinical monitoring in acid sphingomyelinase deficiency in Turkey: a pediatric metabolic disease specialist's perspective.

This review by a panel of pediatric metabolic disease specialists aimed to provide a practical and implementable guidance document to assist clinicians in best clinical practice in terms of recognition, diagnosis and management of patients with acid sphingomyelinase deficiency (ASMD). The participating experts consider the clinical suspicion of ASMD by the physician to be of utmost importance in the prevention of diagnostic delay and strongly suggest the use of a diagnostic algorithm including/starting with dried blood spots assay in the timely diagnosis of ASMD in patients presenting with hepatosplenomegaly and a need for increased awareness among physicians in this regard to consider ASMD in the differential diagnosis. In anticipation of the introduction of enzyme replacement therapy, raising awareness of the disease among physicians to prevent diagnostic delay and further investigation addressing natural history of ASMD across the disease spectrum, potential presenting characteristics with a high index of suspicion, as well as biomarkers and genotype-phenotype correlations suggestive of poor prognosis seem important in terms of implementation of best practice patterns.

Triosephosphate Isomerase Deficiency: E105D Mutation in Unrelated Patients and Review of the Literature.

Introduction: Chronic haemolytic anaemia, increased susceptibility to infections, cardiomyopathy, neurodegeneration, and death in early childhood are the clinical findings of triosephosphate isomerase (TPI) deficiency, which is an ultra-rare disorder. The clinical and laboratory findings and the outcomes of 2 patients with TPI deficiency are reported, with a review of cases reported in the literature. Case Presentation: Two unrelated patients with haemolytic anaemia and neurologic findings who were diagnosed as having TPI deficiency are presented. Neonatal onset of initial symptoms was observed in both patients, and the age at diagnosis was around 2 years. The patients had increased susceptibility to infections and respiratory failure, but cardiac symptoms were not remarkable. Screening for inborn errors of metabolism revealed a previously unreported metabolic alteration determined using tandem mass spectrometry in acylcarnitine analysis, causing elevated propionyl carnitine levels in both patients. The patients had p.E105D (c.315G>C) homozygous mutations in the TPI1 gene. Although severely disabled, both patients are alive at the ages of 7 and 9 years. Discussion: For better management, it is important to investigate the genetic aetiology in patients with haemolytic anaemia with or without neurologic symptoms who do not have a definitive diagnosis. The differential diagnosis of elevated propionyl carnitine levels using tandem mass spectrometry screening should also include TPI deficiency.

Evaluation of the risk factors for noncommunicable diseases in patients with inborn errors of amino acid metabolism receiving nutrition therapy.

OBJECTIVES: There is growing concern about the low-protein and high-energy diet therapies used in the treatment of inherited amino acid metabolism disorders. We aimed to identify the risk factors for noncommunicable diseases that may arise from nutritional therapies and suggests approaches that may prevent the development of the noncommunicable diseases. METHODS: The present study evaluates 112 patients, on long-term nutritional therapy for at least the last 2 years with a diagnosis of an inborn error of the amino acid metabolism, and their 28 healthy siblings. The participants are assessed for the development of overweight and metabolic syndrome based on an analysis of anthropometric parameters, body composition and the results of biochemical tests. RESULTS: Anthropometric measurements including BMI, weight Z-score, waist circumference and fat mass were not significantly different between patients and controls. Height Z-scores were similar in phenylketonuria patients compared to controls, but lower in urea cycle disorders, organic acidemia and maple syrup urine disease groups. No increased risk of development of overweight or metabolic syndrome was detected in the patient group, while there were findings suggesting malnutrition in patients diagnosed with urea cycle disorders. There was a correlation between patients' BMI and C3-carnitine levels in organic acidemia patients and leucine levels in maple syrup urine disease patients. CONCLUSIONS: All forms of malnutrition can be prevented in patient groups receiving limited nutrients under a dietary management protocol, based on the findings of anthropometric and biochemical evaluations and analyses of body composition.

Clinical and bi-genomic DNA findings of patients suspected to have mitochondrial diseases.

Background: Mitochondrial diseases are the most common group of inherited metabolic disorders, causing difficulties in definite diagnosis due to clinical and genetic heterogeneity. Clinical components are predominantly associated with pathogenic variants shown in nuclear or mitochondrial genomes that affect vital respiratory chain function. The development of high-throughput sequencing technologies has accelerated the elucidation of the genetic etiology of many genetic diseases that previously remained undiagnosed. Methods: Thirty affected patients from 24 unrelated families with clinical, radiological, biochemical, and histopathological evaluations considered for mitochondrial diseases were investigated. DNA isolated from the peripheral blood samples of probands was sequenced for nuclear exome and mitochondrial DNA (mtDNA) analyses. MtDNA sequencing was also performed from the muscle biopsy material in one patient. For segregation, Sanger sequencing is performed for pathogenic alterations in five other affected family members and healthy parents. Results: Exome sequencing revealed 14 different pathogenic variants in nine genes encoding mitochondrial function peptides (AARS2, EARS2, ECHS1, FBXL4, MICOS13, NDUFAF6, OXCT1, POLG, and TK2) in 12 patients from nine families and four variants in genes encoding important for muscle structure (CAPN3, DYSF, and TCAP) in six patients from four families. Three probands carried pathogenic mtDNA variations in two genes (MT-ATP6 and MT-TL1). Nine variants in five genes are reported for the first time with disease association: (AARS2: c.277C>T/p.(R93*), c.845C>G/p.(S282C); EARS2: c.319C>T/p.(R107C), c.1283delC/p.(P428Lfs*); ECHS1: c.161G>A/p.(R54His); c.202G>A/p.(E68Lys); NDUFAF6: c.479delA/p.(N162Ifs*27); and OXCT1: c.1370C>T/p.(T457I), c.1173-139G>T/p.(?). Conclusion: Bi-genomic DNA sequencing clarified genetic etiology in 67% (16/24) of the families. Diagnostic utility by mtDNA sequencing in 13% (3/24) and exome sequencing in 54% (13/24) of the families prioritized searching for nuclear genome pathologies for the first-tier test. Weakness and muscle wasting observed in 17% (4/24) of the families underlined that limb-girdle muscular dystrophy, similar to mitochondrial myopathy, is an essential point for differential diagnosis. The correct diagnosis is crucial for comprehensive genetic counseling of families. Also, it contributes to making treatment-helpful referrals, such as ensuring early access to medication for patients with mutations in the TK2 gene.

Molecular genetics of maple syrup urine disease in the Turkish population.

In maple syrup urine disease (MSUD), disease-causing mutations can affect the BCKDHA, BCKDHB or DBT genes encoding for the E1alpha, E1beta and E2 subunits of the multienzyme branched-chain alpha-keto acid dehydrogenase (BCKDH) complex. Here we summarize the MSUD genotypes of a cohort of 32 unrelated Turkish patients in whom both alleles at a single gene locus harbored presumable disease-causing nucleotide changes. The patients had different forms of MSUD, ranging from the severe classical form (26 patients) to severe and mild variants (6 patients). In all except two patients (92%), the mutations occurred homozygously. The mutational spectrum included 27 different sequence variations--12 changes in the BCKDHA, 10 in the BCKDHB, and 5 in the DBT genes. In 37% (12 patients) of a total of 64 alleles, the supposed disease-causing mutations were located in the BCKDHA gene, in 44% (14 patients) in the BCKDHB gene and in 19% (6 patients) in the DBT gene. The mutational profile is heterogeneous, although two mutations occurred three times and five mutations occurred twice. There was no cluster for a single mutation except for c.773G>A (p.Cys258Tyr) in the BCKDHA gene, a hypothetical founder mutation in the Camlidere population.