Impact of citrulline substitution on clinical outcome after liver transplantation in carbamoyl phosphate synthetase 1 and ornithine transcarbamylase deficiency

Carbamoyl phosphate synthetase 1 (CPS1) and ornithine transcarbamylase (OTC) deficiencies are rare urea cycle disorders, which can lead to life-threatening hyperammonemia. Liver transplantation (LT) provides a cure and offers an alternative to medical treatment and life-long dietary restrictions with permanent impending risk of hyperammonemia. Nevertheless, in most patients, metabolic aberrations persist after LT, especially low plasma citrulline levels, with questionable clinical impact. So far, little is known about these alterations and there is no consensus, whether l-citrulline substitution after LT improves patients' symptoms and outcomes. In this multicentre, retrospective, observational study of 24 patients who underwent LT for CPS1 (n = 11) or OTC (n = 13) deficiency, 25% did not receive l-citrulline or arginine substitution. Correlation analysis revealed no correlation between substitution dosage and citrulline levels (CPS1, p = 0.8 and OTC, p = 1). Arginine levels after liver transplantation were normal after LT independent of citrulline substitution. Native liver survival had no impact on mental impairment (p = 0.67). Regression analysis showed no correlation between l-citrulline substitution and failure to thrive (p = 0.611) or neurological outcome (p = 0.701). Peak ammonia had a significant effect on mental impairment (p = 0.017). Peak plasma ammonia levels correlate with mental impairment after LT in CPS1 and OTC deficiency. Growth and intellectual impairment after LT are not significantly associated with l-citrulline substitution.

Biallelic hypomorphic variants in CAD cause uridine-responsive macrocytic anaemia with elevated haemoglobin-A2

Biallelic pathogenic variants in CAD, that encode the multienzymatic protein required for de-novo pyrimidine biosynthesis, cause early infantile epileptic encephalopathy-50. This rare disease, characterized by developmental delay, intractable seizures and anaemia, is amenable to treatment with uridine. We present a patient with macrocytic anaemia, elevated haemoglobin-A2 levels, anisocytosis, poikilocytosis and target cells in the blood smear, and mild developmental delay. A next-generation sequencing panel revealed biallelic variants in CAD. Functional studies did not support complete abrogation of protein function; however, the patient responded to uridine supplement. We conclude that biallelic hypomorphic CAD variants may cause a primarily haematological phenotype.

A novel SLC25A13 gene splice site variant causes Citrin deficiency in an infant

Citrin deficiency is an autosomal recessive disorder associated with SLC25A13 gene pathogenic variants, with more than a hundred known at present. It manifests in neonates as failure to thrive and acute liver insufficiency. We herein describe a case of a 4-week-old infant who presented with insufficient weight gain and liver failure accompanied by hyperammonemia. She was diagnosed with Citrin deficiency after a thorough biochemical and molecular analysis including amino acid profile, DNA sequencing of genes of interest and RNA splice site evaluation, to reveal a yet unknown damaging variant of the SLC25A13 gene.

Clinical score for early diagnosis and treatment of stroke-like episodes in MELAS syndrome

BACKGROUND AND OBJECTIVES

Stroke-like episodes (SLEs) in patients with MELAS syndrome are often initially misdiagnosed as acute ischemic stroke (AIS), resulting in treatment delay. We aimed to determine clinical features that may distinguish SLEs from AISs and explore the benefit of early L-arginine treatment on patient outcomes.

METHODS

We looked retrospectively for MELAS patients admitted between January 2005 and January 2022 and compared them to an AIS cohort with similar lesion topography. MELAS patients who received L-arginine within 40 days of their first SLE were defined as the early treatment group and the remaining as late or no treatment group.

RESULTS

Twenty-three SLEs in 10 MELAS patients and 21 AISs were included. SLE patients had significantly different features: they were younger, more commonly reported hearing loss, lower body mass index, had more commonly a combination of headache and/or seizures at presentation, serum lactate was higher, and hemiparesis was less common. An SLE Early Clinical Score (SLEECS) was constructed by designating one point to each above features. SLEECS ≥ 4 had 80% sensitivity and 100% specificity for SLE diagnosis. Compared to late or no treatment, early treatment group patients (n = 5) had less recurrent SLEs (total 2 vs. 11), less seizures (14% vs. 25%, p = 0.048), lower degree of disability at first and last follow-up (modified ranking scale, mRS 2 ± 0.7 vs. 4.2 ± 1, p = 0.005; 2 ± 0.7 vs. 5.8 ± 0.5, p < 0.001, respectively), and a lower mortality (0% vs. 80% p = 0.048).

CONCLUSIONS

The SLEECS model may aid in the early diagnosis and treatment of SLEs and lead to improved clinical outcomes.

The effects of the COVID-19 pandemic on patients with lysosomal storage disorders in Israel

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) is the causative agent of the current COVID-19 pandemic. Lysosomal storage disorders (LSD) comprise of 70 inherited inborn errors of metabolism. Affected individuals suffer from multi-systemic involvement with variable severity and rate of disease progression between different diseases. Some of the LSDs have established treatments, whether parenteral or oral therapies. The full impact of the COVID-19 pandemic together with the lockdown on the wellbeing and medical management of patients with rare diseases, such as LSDs, is widely unknown. Herein, we describe the effects of the COVID-19 pandemic and its associated mandatory home lockdown on patients with LSDs in Israel.

RESULTS

We present a prospective multi-center questionnaire study including 48 LSD patients from four medical centers in Israel. The study objective was to assess the impact of the COVID-19 pandemic restrictions on individuals with LSDs in Israel, as reported by their caregivers. Secondary objectives were to assess the morbidity from SARS CoV-2 in LSD patients and the impact of changes in mood and behavior on compliance to treatment and to assess the relationship between changes in mood to changes in cognition and behavior. Thirty one of 38 patients (82%) who received any kind of regular treatment did not miss treatments. Among patients receiving enzyme replacement therapy (ERT) in the in-hospital setting, 5 patients (20%) experienced treatment disruptions. Four patients had tested positive for SARS-Cov-2 virus infection by PCR. Seven out of the 48 patients (14%) described mood changes with cognitive and motor deterioration during the home quarantine.

CONCLUSIONS

We observed high rates of treatment adherence and low morbidity through the COVID-19 pandemic in patients with LSDs in Israel. LSDs patients can be a model for patients with complex chronic diseases requiring routine treatments and surveillance during a pandemic or other disruption of daily routine.

Four patients with D-bifunctional protein (DBP) deficiency: Expanding the phenotypic spectrum of a highly variable disease

Introduction

Peroxisomal D-bifunctional protein (DBP) deficiency is an autosomal recessive disorder historically described as a Zellweger-like syndrome comprising neonatal seizures, retinopathy, hearing loss, dysmorphic features, and other complications. The HSD17B4 gene encodes DBP which is essential for oxidation of peroxisomal substrates. We describe 4 patients - 2 unrelated female girls and 2 monozygotic twin sisters - with DBP deficiency and phenotypic diversity.

Patient reports

Patient 1 presented neonatally with hypotonia and seizures, and later on developed global developmental delay and regression, sensorineural hearing loss, nystagmus and cortical blindness. The brain MRI demonstrated bilateral peri-sylvian polymicrogyria. Whole exome sequencing revealed 2 mutations in the HSD17B4 gene (c.752G>A, p.(Arg251Gln); c.868 + 1delG).Patient 2 presented with hypotonia, motor delay, and sensorineural hearing loss in infancy, considerable developmental regression during her fourth year, nystagmus, and peripheral neuropathy. Brain MRI demonstrated cerebellar atrophy and abnormal basal ganglia and white matter signal, which appeared after the age of two years. Whole exome sequencing revealed 2 mutations in the HSD17B4 gene (c.14 T>G, p.(Leu5Arg); c.752G>A, p.(Arg251Gln)).Patients 3 and 4, two female monozygotic twins, presented with hypotonia, developmental delay, and macrocephaly from birth, and later on also sensorineural hearing loss, infantile spasms and hypsarrhythmia, and adrenal insufficiency. Brain MRI demonstrated delayed myelination, and an assay of peroxisomal beta oxidation suggested DBP deficiency. Sequencing of the HSD17B4 gene revealed the same 2 mutations as in patient 1.

Discussion

We describe 4 patients with variable and diverse clinical picture of DBP deficiency and particularly emphasize the clinical, biochemical, and neuroimaging characteristics. Interestingly, the clinical phenotype varied even between patients with the exact two mutations in the HSD17B4 gene. In addition, in two of the three patients in whom levels of VLCFA including phytanic acid were measured, the levels were within normal limits. This is expanding further the clinical spectrum of this disorder, which should be considered in the differential diagnosis of every patient with hypotonia and developmental delay especially if accompanied by polymicrogyria, seizures, sensorineural hearing loss, or adrenal insufficiency regardless of their VLCFA profile.

The natural history of classic galactosemia: lessons from the GalNet registry

BACKGROUND

Classic galactosemia is a rare inborn error of carbohydrate metabolism, caused by a severe deficiency of the enzyme galactose-1-phosphate uridylyltransferase (GALT). A galactose-restricted diet has proven to be very effective to treat the neonatal life-threatening manifestations and has been the cornerstone of treatment for this severe disease. However, burdensome complications occur despite a lifelong diet. For rare diseases, a patient disease specific registry is fundamental to monitor the lifespan pathology and to evaluate the safety and efficacy of potential therapies. In 2014, the international Galactosemias Network (GalNet) developed a web-based patient registry for this disease, the GalNet Registry. The aim was to delineate the natural history of classic galactosemia based on a large dataset of patients.

METHODS

Observational data derived from 15 countries and 32 centers including 509 patients were acquired between December 2014 and July 2018.

RESULTS

Most affected patients experienced neonatal manifestations (79.8%) and despite following a diet developed brain impairments (85.0%), primary ovarian insufficiency (79.7%) and a diminished bone mineral density (26.5%). Newborn screening, age at onset of dietary treatment, strictness of the galactose-restricted diet, p.Gln188Arg mutation and GALT enzyme activity influenced the clinical picture. Detection by newborn screening and commencement of diet in the first week of life were associated with a more favorable outcome. A homozygous p.Gln188Arg mutation, GALT enzyme activity of ≤ 1% and strict galactose restriction were associated with a less favorable outcome.

CONCLUSION

This study describes the natural history of classic galactosemia based on the hitherto largest data set.

Long-term outcome of expanded newborn screening at Boston children's hospital: benefits and challenges in defining true disease

INTRODUCTION

There is no universal consensus of the disorders included in newborn screening programs. Few studies so far, mostly short-term, have compared the outcome of disorders detected by expanded newborn screening (ENBS) to the outcome of the same disorders detected clinically.

METHODS

We compared the clinical and neurodevelopmental outcomes in patients with metabolic disorders detected by ENBS, including biotinidase testing, with those detected clinically and followed at the Metabolism Clinic at Boston Children's Hospital.

RESULTS

One hundred eighty-nine patients came to attention from ENBS and 142 were clinically diagnosed. 3-methylcrotonyl-CoA carboxylase, biotinidase, and carnitine deficiencies were exclusively identified by ENBS and medium chain acyl-CoA dehydrogenase (MCADD) and very long chain acyl-CoA dehydrogenase deficiencies (VLCADD) were predominantly identified by ENBS whereas the organic acid disorders more often came to attention clinically. Only 2% of the ENBS-detected cases had clinically severe outcomes compared to 42% of those clinically detected. The mean IQ score was 103 + 17 for the ENBS-detected cases and 77 + 24 for those clinically detected. Those newly included disorders that seem to derive the greatest benefit from ENBS include the fatty acid oxidation disorders, profound biotinidase deficiency, tyrosinemia type 1, and perhaps carnitine deficiency.

CONCLUSION

Although the NBS-identified and clinically-identified cohorts were not completely comparable, this long-term study shows likely substantial improvement overall in the outcome of these metabolic disorders in the NBS infants. Infants with mild disorders and benign variants may represent a significant number of infants identified by ENBS. The future challenge will be to unequivocally differentiate the disorders most benefitting from ENBS and adjust programs accordingly.

Pediatric Neurologic Complications Associated With Influenza A H1N1

Influenza is associated with a variety of neurologic complications. Although the epidemiologic and clinical characteristics of influenza A H1N1 were reviewed in depth, only brief descriptions of neurologic complications exist. We describe the neurologic complications of children hospitalized with influenza A H1N1 infection. We undertook a retrospective study of all hospitalized children with laboratory-confirmed influenza A H1N1 infection accompanied by neurologic complications during a 4-month winter period. Their demographics and clinical characteristics of neurologic presentations were reviewed. Fourteen of 74 children (19%) with laboratory-confirmed influenza A H1N1 infection presented with neurologic complications. Eleven (11/14, 79%) were previously healthy, and three exhibited chronic conditions. Ten (10/14, 71%) presented with seizures: six were febrile, and four were nonfebrile. Other complications included transverse myelitis, myositis, expressive aphasia, and syncope. Only the child with transverse myelitis required a course of rehabilitation. Neurologic complications associated with influenza A H1N1 in our patients were relatively mild. Seizures (febrile or nonfebrile) were the most common. However, the possibility of influenza A H1N1 infection should be borne in mind when diagnosing children with neurologic signs during the influenza A H1N1 season.

Management of children with nonfebrile seizures in the emergency department

BACKGROUND

Children with seizures are often referred to the emergency department where they are typically evaluated by a physician with limited knowledge of pediatric epileptology and undergo a costly and extensive work-up that contributes little to the final decision.

AIM

The aim of this study was to examine the medical management of children with nonfebrile seizures in the emergency department and to define the potential role of the neurology clinic in this context.

MATERIALS AND METHODS

The files of 85 children who made 104 visits to the emergency department of a pediatric tertiary hospital for nonfebrile seizures were retrospectively reviewed.

RESULTS

Average age was 7.5 years. Blood tests were performed in almost all visits; a minority also involved the use of brain scans and electroencephalography. A neurologist was consulted in about half the visits. Only electroencephalography and neurologic consultation contributed significantly to the final decision. Hospitalization was recommended in 71% of cases, but it was usually short term and not accompanied by significant changes in the management.

CONCLUSION

In children with nonfebrile seizures, a problem-oriented approach including only the necessary work-up (e.g. electroencephalography) with neurologist consultation can potentially decrease the inpatient load and lower health care costs, while sparing patients unnecessary tests.

Cognition, attention, and behavior in Prader-Willi syndrome

We studied the academic, cognitive, and behavior profile of 18 patients with Prader-Willi syndrome. All had severe learning disabilities in arithmetic and writing, and the majority were also dyslexic. Their average Full-Scale IQ was 73.7 +/- 8.9, which was 1 SD below normal range, whereas their performance on executive, memory, and visuospatial tasks ranged from 2.1 to 7.0 SD below the expected means. Behavioral problems were measured using the Child Behavior Checklist, on which the majority scored in the pathologic range for social and attention problems, delinquent and aggressive behavior, somatic complaints, and thought problems. Genotypes of the children did not predict cognitive or behavioral profile, nor could behavior be associated with parameters of weight or IQ. In summary, we found that patients with Prader-Willi syndrome have profound learning disabilities and cognitive deficits, greater than expected for their IQ. Behavioral problems, including attention-deficit hyperactivity disorder (ADHD), are also prevalent and impede the overall management of this group of patients. The genotypes were not helpful in predicting cognitive or behavioral patterns.

[Prader-Willi syndrome: medical, emotional and cognitive facets]

Prader-Willi syndrome, first described in 1956, is characterized by marked hypotonia, hyperphagia, severe obesity, short stature, hypogonadism, orthopedic problems, breathing-related sleep disorders, mild to moderate mental retardation and behavioral abnormalities. The incidence of this syndrome, an expression of a genetic imprinting error in chromosome 15, is 1:10,000-1:25,000. We describe the medical, emotional and cognitive parameters of 34 patients in our multidisciplinary clinic for Prader-Willi syndrome. Their ages range from 5 months to 40 years and 20 are males. Excessive weight gain started at the age of 6 years, increasing to 170-370% of that predicted by height and age and short stature started after the age of 12. All males have hypogonadism; 6 patients have scoliosis. Breathing-related sleep disorders have occurred in 15. Children above the age of 8 years underwent neuropsychological assessment: half (9/18) have borderline intelligence while a quarter have low-normal intelligence and the remainder mild to moderate mental retardation. Behavioral and social problems are common, and become more prominent during adolescence. ADHD was diagnosed in 10/18.

Attention-deficit hyperactivity disorder and developmental right-hemisphere syndrome: congruence and incongruence of cognitive and behavioral aspects of attention

We studied clinical aspects of attention in three groups: children with developmental right-hemisphere syndrome and attention-deficit hyperactivity disorder (ADHD), children with ADHD only, and normal controls. The three groups (N = 54) were case-matched for age, sex, IQ, hand dominance, and socioeconomic status. ADHD was diagnosed clinically using the Diagnostic and Statistical Manual of Mental Disorders-III-Revised criteria and the Conners' Abbreviated Teacher Questionnaire. Additional aspects of attention and behavior were measured by the Child Behavior Checklist, a low-cognitive-load continuous performance task, and the visual target cancellation test (paper and pencil). Although the Child Behavior Checklist profile of attentional deficits in the two clinical groups was similar, we found that the developmental right-hemisphere syndrome group was more severely impaired on parameters of attention measured by the continuous performance task and visual target cancellation test than the children with ADHD. We conclude that the profile of attentional deficits in developmental right-hemisphere syndrome is different than that seen in children with ADHD only, possibly reflecting disparate neurologic underpinnings for the two syndromes.

[Attention deficit disorder: attentional characteristics of developmental right hemisphere syndrome]

Developmental right hemisphere syndrome (DRHS) is characterized by emotional and interpersonal difficulties, attention deficit hyperactivity disorder (ADHD), visuo-spatial handicaps, subtle left body neurologic signs and failure in nonverbal academic domains, especially arithmetic. Concurrence of ADHD and DRHS is not surprising because research has implicated dysfunction of the right hemisphere in both syndromes. Furthermore, the right hemisphere has more brain areas devoted to attentional processing, making it more important and more vulnerable in attentional problems. We describe the clinical parameters of DRHS as exemplified by 2 cases, a boy and a girl, both 13 years old. They participated in a study group in which attention and speed of performance were assessed in children with DRHS and were compared to children with ADHD and to a control group. A tendency to overfocusing, difficulty in inhibition, perseverative behaviors, stereotypy, and slowness and absence of hyperactivity characterized the DRHS group. These behaviors led us to hypothesize that the attentional symptoms in DRHS define a specific subgroup of ADHD which requires a different therapeutic approach.