Novel GALT variations and genetic spectrum in Turkish population with the correlation of genotype and phenotype

Classic galactosemia (OMIM#230400) is an autosomal recessive inborn error of carbohydrate metabolism caused by a deficiency of the galactose-1-phosphate-uridyl-transferase enzyme encoded by the GALT gene. Even though a galactose-restricted diet efficiently resolves the acute complications, it is insufficient to prevent long-term complications regarding speech defects, intellectual functioning, premature ovarian failure, cataract, hepatomegaly, dysarthria, ataxia, and tremor. Seventy-seven patients who were genetically diagnosed with classic galactosemia were included in this cohort. Identified novel variants were classified based on their predicted effect on the GALT function. Further, potential genotype-phenotype correlations were investigated via statistical analysis. In total, 18 different sequence variants were identified, including four novels (c.200delG/p.(Arg67Profs* 19), c.533T>G/ p.(Met178Arg), c.708_709delGT/p.(Ser236Argfs* 30), c.467C>A/p.(Ser156* )). Jaundice was the most common short-term finding with 80% (61/77). Even with early diagnosis, intellectual disability is encountered with 36% (27/74) of the long-term complications. Patients with biallelic missense variants have a significantly higher prevalence of cataracts (OR: 17.9). Longitudinal observations showed attenuation of cataracts and hepatomegaly. This study has shown the GALT variation spectrum of the Turkish population with a 30-year retrospective cohort, submitting a significant contribution to the genotype/phenotype correlation in galactosemia. This study also highlights the cost-effective importance of Sanger sequencing in the diagnosis of single-gene metabolic diseases.

Reanalysis of exome sequencing data reveals a treatable neurometabolic origin in two previously undiagnosed siblings with neurodevelopmental disorder

Neurodevelopmental disorders (NDDs) have broad heterogeneity both clinically and genetically. Inborn errors of metabolism can be one of the reasons of neurodevelopmental disruption causing specific NDDs. Although there is tremendous advance in molecular identification via next-generation sequencing (NGS), there are still many unsolved patients with NDD. Reanalysis of NGS data with different pipelines can at least partially accomplish this challenge. Herein, we report clinic and genetic components of an adult sib-pair with an undiagnosed NDD condition, which has been solved through reanalysis of whole-exome sequencing (WES). Parallel analysis of SNP-based genotyping and WES was performed to focus on variants only in loci with positive logarithm of the odds scores. WES data was analyzed through three different pipelines with two distinct bed files. Reanalysis of WES data led us to detect a homozygous FOLR1 variant (ENST00000393676.5:c.610C > T, p.(Arg204Ter), rs952165627) in the affected sib-pair. Surprisingly, the variant could not be detected in the first analysis as the variant region is not included in the first bed file which may frequently be used. Biochemical tests of CSF have confirmed the genetic analysis, CSF folic acid levels were detected low in sib-pair, and intravenous folinic acid treatment improved the disease course for the first 6 months of follow-up even at late diagnosis age. Although combined analysis of SNP-based genotyping and WES is a powerful tool to reveal the genetic components of heterogeneous diseases, reanalysis of genome data still should be considered in unsolved patients. Also, biochemical screening helps us to decipher undiagnosed NDD that may be a treatable neurometabolic condition.

Expert-opinion-based guidance for the care of children with lysosomal storage diseases during the COVID-19 pandemic: An experience-based Turkey perspective

This expert-opinion-based document was prepared by a group of specialists in pediatric inherited metabolic diseases and infectious diseases including administrative board members of Turkish Society for Pediatric Nutrition and Metabolism to provide guidance for the care of children with lysosomal storage disorders (LSDs) during the COVID-19 pandemic in Turkey. The experts reached consensus on key areas of focus regarding COVID-19-based risk status in relation to intersecting immune-inflammatory mechanisms and disease patterns in children with LSDs, diagnostic virus testing, particularly preventive measures and priorities during the pandemic, routine screening and diagnostic interventions for LSDs, psychological and socioeconomic impact of confinement measures and quarantines and optimal practice patterns in managing LSDs and/or COVID-19. The participating experts agreed on the intersecting characteristics of immune-inflammatory mechanisms, end-organ damage and prognostic biomarkers in LSD and COVID-19 populations, emphasizing the likelihood of enhanced clinical care when their interaction is clarified via further studies addressing certain aspects related to immunity, lysosomal dysfunction and disease pathogenesis. In the context of the current global COVID-19 pandemic, this expert-opinion-based document provides guidance for the care of children with LSDs during the COVID-19 pandemic based on the recent experience in Turkey.

Three-Country Snapshot of Ornithine Transcarbamylase Deficiency

X-linked ornithine transcarbamylase deficiency (OTCD) is the most common urea cycle defect. The disease severity ranges from asymptomatic carrier state to severe neonatal presentation with hyperammonaemic encephalopathy. We audited the diagnosis and management of OTCD, using an online 12-question-survey that was sent to 75 metabolic centres in Turkey, France and the UK. Thirty-nine centres responded and 495 patients were reported in total. A total of 208 French patients were reported, including 71 (34%) males, 86 (41%) symptomatic and 51 (25%) asymptomatic females. Eighty-five Turkish patients included 32 (38%) males, 39 (46%) symptomatic and 14 (16%) asymptomatic females. Out of the 202 UK patients, 66 (33%) were male, 83 (41%) asymptomatic and 53 (26%) symptomatic females. A total of 19%, 12% and 7% of the patients presented with a neonatal-onset phenotype in France, Turkey and the UK, respectively. Vomiting, altered mental status and encephalopathy were the most common initial symptoms in all three countries. While 69% in France and 79% in Turkey were receiving protein restriction, 42% were on a protein-restricted diet in the UK. A total of 76%, 47% and 33% of patients were treated with ammonia scavengers in Turkey, France and the UK, respectively. The findings of our audit emphasize the differences and similarities in manifestations and management practices in three countries.

Functional Connectivity Analysis in Heterozygous Glucocerebrosidase Mutation Carriers

BACKGROUND

There is evidence that alterations in functional connectivity (FC) of the striatocortical circuits may appear before the onset of clinical symptoms of Parkinson's disease (PD).

OBJECTIVE

The aim of this study was to investigate FC of the striatocortical circuitry in asymptomatic carriers of heterozygous glucocerebrosidase (GBA) mutations, which pose a significant risk for developing PD.

METHODS

Twenty-one parents of confirmed Gaucher disease patients who were carrying heterozygous GBA mutations and 18 healthy individuals matched for age and gender were included. GBA mutation analysis was performed in all participants. Clinical evaluation included neurological examination, Mini Mental State Examination, and UPDRS Part III. Structural and functional MRI data of 18 asymptomatic GBA mutation carriers (asGBAmc) and 17 healthy controls (HC) were available. FC was analyzed with seed-based approach.

RESULTS

Eleven asymptomatic mutation carriers had heterozygous p.L483P mutation, 6 subjects heterozygous p.N409S mutation and 1 subject heterozygous p.R392G mutation in GBA gene. Mini-Mental State Examination mean score was 28.77 (±1.16) and 29.64 (±0.70) in asGBAmc and HC groups, respectively (p = 0.012). Significant increased connectivityConclusion:Our results suggest that alterations in striatocortical FC can be detected in asymptomatic heterozygous GBA mutation carriers who are at risk of developing PD. These findings may provide insight into network changes during the asymptomatic phase of PD.

ASAH1 pathogenic variants associated with acid ceramidase deficiency: Farber disease and spinal muscular atrophy with progressive myoclonic epilepsy

Farber disease and spinal muscular atrophy with progressive myoclonic epilepsy are a spectrum of rare lysosomal storage disorders characterized by acid ceramidase deficiency (ACD), resulting from pathogenic variants in N-acylsphingosine amidohydrolase 1 (ASAH1). Other than simple listings provided in literature reviews, a curated, comprehensive list of ASAH1 mutations associated with ACD clinical phenotypes has not yet been published. This publication includes mutations in ASAH1 collected through the Observational and Cross-Sectional Cohort Study of the Natural History and Phenotypic Spectrum of Farber Disease (NHS), ClinicalTrials.gov identifier NCT03233841, in combination with an up-to-date curated list of published mutations. The NHS is the first to collect retrospective and prospective data on living and deceased patients with ACD presenting as Farber disease, who had or had not undergone hematopoietic stem cell transplantation. Forty-five patients representing the known clinical spectrum of Farber disease (living patients aged 1-28 years) were enrolled. The curation of known ASAH1 pathogenic variants using a single reference transcript includes 10 previously unpublished from the NHS and 63 that were previously reported. The publication of ASAH1 variants will be greatly beneficial to patients undergoing genetic testing in the future by providing a significantly expanded reference list of disease-causing variants.

Primary coenzyme Q10 Deficiency-6 (COQ10D6): Two siblings with variable expressivity of the renal phenotype

Primary coenzyme Q10 deficiency-6 (COQ10D6) is a rare autosomal recessive disorder caused by COQ6 mutations. The main clinical manifestations are infantile progressive nephrotic syndrome (NS) leading to end-stage renal disease and sensorineural deafness. A 7-year-old girl was diagnosed with steroid-resistant NS (SRNS) and an audiological work-up revealed bilateral sensorineural deafness. A renal biopsy demonstrated focal segmental glomerulosclerosis. Despite immunosuppressive therapy, her serum levels of creatinine increased and haemodialysis was indicated within 1 year after the diagnosis. Living-donor kidney transplantation was performed in the eighth month of haemodialysis. A diagnostic custom-designed panel-gene test including 30 genes for NS revealed homozygous c.1058C > A [rs397514479] in exon nine of COQ6. Her older brother, who had sensorineural hearing loss with no renal or neurological involvement, had the same mutation in homozygous form. COQ6 mutations should be considered not only in patients with SRNS with sensorineural hearing loss but also in patients with isolated sensorineural hearing loss with a family history of NS. The reported p.His174 variant of COQ8B was suggested to be a risk factor for secondary CoQ deficiency, while p.Arg174 appeared to improve the condition in a yeast model. Family segregation and the co-occurrence of biallelic p.Arg174 of COQ8B in a brother with hearing loss implied that the interaction of the altered COQ8B with the mutant COQ6 alleviated the symptoms in this family. CoQ10 replacement therapy should be initiated for these patients, as primary CoQ10 deficiency is considered the only known treatable mitochondrial disease.

Determinants of Plasma Docosahexaenoic Acid Levels and Their Relationship to Neurological and Cognitive Functions in PKU Patients: A Double Blind Randomized Supplementation Study

Children with phenylketonuria (PKU) follow a protein restricted diet with negligible amounts of docosahexaenoic acid (DHA). Low DHA intakes might explain subtle neurological deficits in PKU. We studied whether a DHA supply modified plasma DHA and neurological and intellectual functioning in PKU. In a double-blind multicentric trial, 109 PKU patients were randomized to DHA doses from 0 to 7 mg/kg&day for six months. Before and after supplementation, we determined plasma fatty acid concentrations, latencies of visually evoked potentials, fine and gross motor behavior, and IQ. Fatty acid desaturase genotypes were also determined. DHA supplementation increased plasma glycerophospholipid DHA proportional to dose by 0.4% DHA per 1 mg intake/kg bodyweight. Functional outcomes were not associated with DHA status before and after intervention and remained unchanged by supplementation. Genotypes were associated with plasma arachidonic acid levels and, if considered together with the levels of the precursor alpha-linolenic acid, also with DHA. Functional outcomes and supplementation effects were not significantly associated with genotype. DHA intakes up to 7 mg/kg did not improve neurological functions in PKU children. Nervous tissues may be less prone to low DHA levels after infancy, or higher doses might be required to impact neurological functions. In situations of minimal dietary DHA, endogenous synthesis of DHA from alpha-linolenic acid could relevantly contribute to DHA status.

A study on neonatal factors and eruption time of primary teeth

OBJECTIVE

The purpose of this study was to determine the time of the eruption of the first primary tooth (FPT) in infants and to assess the effects of neonatal factors on the timing of the eruption.

BASIC RESEARCH DESIGN

The dental and medical records of healthy infants were reviewed to gather data on birth weight (BW), gestational age (GA), prenatal history, and the time of the eruption of the FPT. Additionally, the mothers of these infants were asked to identify their smoking habits and/or caffeine consumption during pregnancy through face-to-face interviews. The resulting data were statistically analysed with the Student's t, Tukey, and Pearson correlation tests.

RESULTS

The mean eruption times (MET) for girls and boys were 7.25 +/- 2.47 and 7.07 +/- 1.66 months respectively (p > 0.05). The MET of the FPT in infants with a GA of less than 34 weeks, 34 to 37 weeks, or over 37 weeks were 8.0 +/- 2.0, 8.29 +/- 2.97, 6.93 +/- 1.87 months, respectively. The MET in infants with a BW of 1500 to 2500g was 8.28 +/- 2.28 months, while the MET for the infants with a BW of over 2500g was 6.99 +/- 1.94 (p = 0.014).

CONCLUSION

A significant difference was found in the METs of infants with low and normal BWs. No significant differences were observed in the MET as related to other neonatal factors.

Behavioral Approach to Infantile Anorexia and its Outcome on Maternal Psychopathology

Background:

This study aims to examine the effectiveness of a behavioral approach for the treatment of toddlers with infantile anorexia; and the psychopathology and psychological functioning of their mothers before, during and after a structured treatment program.

Method:

Three groups of 30 toddlers of either sex, aged 12 - 36 months (inclusive) were included to the study. The groups consisted of toddlers with 1- Infantile Anorexia 2- Picky Eating and 3- Healthy Eating who were referred for a psychiatric evaluation by pediatricians and gastroenterologists at the Department of Pediatrics, Istanbul School of Medicine. Groups were matched by age, sex, and socioeconomic status. Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), Symptom Check List - 90 (SCL-90), and Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) are used for assessing the maternal psychopathology of cases.

Discussion:

In our sample, mothers of toddlers with IA and PE had more psychiatric symptoms than healthy group. The difference between IA and PE shows that the nutritional status of the child contributes to the psychopathological well-being of the mothers. There was a resolution of depression and anxiety during and after the treatment protocol. Then the psychological status seems to be not the reason but may be the result of the feeding problems. Also interventions that focus primarily on maternal psychopathology may not be effective as a behavioral treatment that focuses on both child and mother.

Breast feeding in organic acidaemias

Breast feeding has been recommended for the dietary treatment of infants with organic acidaemias, but studies documenting clinical experience are still very few. Nine infants, diagnosed with methylmalonic acidaemia (n = 4), propionic acidaemia (n = 1), isovaleric acidaemia (n = 2) and glutaric acidaemia type I (n = 2) were breast fed after diagnosis. The age of the patients was 28.9+/- 13.4 months (mean +/- SD) (range 10-57 months). Eight patients were diagnosed with clinical symptoms and one because of an affected sibling. After the control of acute metabolic problems, an initial period with a measured volume of expressed breast milk was continued with on-demand breast feeding with the addition of a special essential amino acid mixture and energy supplements. Breast feeding was well tolerated in seven infants with good growth, metabolic control and neurological outcome. The duration of breast feeding was 12.3+/- 7.4 months (mean +/- SD) (range 4-24 months) in these patients. Breast feeding was terminated in the patient with propionic acidaemia because of two acute metabolic episodes requiring hospitalization, and could not be continued in one of the patients with isovaleric acidaemia owing to shortage of breast milk. A decrease in the frequency of infections, acute metabolic episodes and hospital admissions was observed in breast-fed infants. Breast feeding of infants with organic acidaemias is feasible with close monitoring of clinical parameters such as growth, development and biochemistry, including amino acids, organic acids and ammonia.

Asymptomatic adults and older siblings with biotinidase deficiency ascertained by family studies of index cases

We report 32 biotinidase-deficient patients detected by family studies in the index cases. The study group consisted of 10 mothers, 4 fathers and 18 siblings. There were 17 individuals (3 mothers, 4 fathers and 10 siblings) with profound biotinidase deficiency (BD) (< 10% of mean normal activity) and 15 (7 mothers and 8 siblings) with partial BD (10-30% of mean normal activity). In the profound BD group, only three siblings were symptomatic. Dermatitis, microcephaly, developmental delay and convulsions were observed. The patients with partial BD did not have any clinical symptoms except one sibling with borderline IQ score. None of the parents was symptomatic. Family investigation of patients with BD is very important for the detection of asymptomatic patients who are at risk of exhibiting symptoms at any age. Careful evaluation of these untreated individuals with BD is important to obtain additional information about the natural history of this disorder and may provide clues to phenotype-genotype relationships and treatment regimes.

Hyperhydroxyprolinaemia detected in newborn screening with tandem mass spectrometry

Hydroxyproline has the same integer molecular weight as leucine and isoleucine and is quantified with these by tandem mass spectrometry. An infant was diagnosed with hyperhydroxyprolinaemia following further evaluation of an elevated "leucine" level in newborn screening by tandem mass spectrometry.

Who lives with whom in Istanbul?

Living groups are an important subject in sociology, demography, economics, social medicine, and anthropology. In many studies, households are chosen as the most suitable unit of investigation, though other choices also have their advantages and limitations (Yanagisako, 1984 pp. 161-205). The household is preferred in the present study, because it enables us to present new information that has been collected by the Turkish census and to discuss its implications for understanding living arrangements during the life course.

An epidemiological approach to acute renal failure in children

The records of 630 pediatric patients with acute renal failure were analysed. Of all patients admitted to the hospital during the same period, 5 per cent had acute renal failure. Newborns and infants constituted 79 per cent of the patients with ARF although this age group comprised only 44 per cent of the general pediatric patients. Acute gastroenteritis and septicaemia were the leading causes of ARF up to 8 years of age. Acute glomerulonephritis took the first place after 8 years of age. Mortality rate of our patients with acute renal failure was 28 per cent.