Pyruvate carboxylase (PC) deficiency is a rare autosomal recessive mitochondrial neurometabolic disorder of energy deficit resulting in high morbidity and mortality, with limited therapeutic options. ...The PC homotetramer has a critical role in gluconeogenesis, anaplerosis, neurotransmitter synthesis, and lipogenesis. The main biochemical and clinical findings in PC deficiency (PCD) include lactic acidosis, ketonuria, failure to thrive, and neurological dysfunction. Use of the anaplerotic agent triheptanoin on a limited number of individuals with PCD has had mixed results. We expand on the potential utility of triheptanoin in PCD by examining the clinical, biochemical, molecular, and health-related quality-of-life (HRQoL) findings in a cohort of 12 individuals with PCD (eight with Type A and two each with Types B and C) treated with triheptanoin ranging for 6 days to about 7 years. The main endpoints were changes in blood lactate and HRQoL scores, but collection of useful data was limited to about half of subjects. An overall trend of lactate reduction with time on triheptanoin was noted, but with significant variability among subjects and only one subject reaching close to statistical significance for this endpoint. Parent reported HRQoL assessments with treatment showed mixed results, with some subjects showing no change, some improvement, and some worsening of overall scores. Subjects with buried amino acids in the pyruvate carboxyltransferase domain of PC that undergo destabilizing replacements may be more likely to respond (with lactate reduction or HRQoL improvement) to triheptanoin compared to those with replacements that disrupt tetramerization or subunit-subunit interface contacts. The reason for this difference is unclear and requires further validation. We observed significant variability but an overall trend of lactate reduction with time on triheptanoin and mixed parent reported outcome changes by HRQoL assessments for subjects with PCD on long-term triheptanoin. The mixed results noted with triheptanoin therapy in this study could be due to endpoint data limitation, variability of disease severity between subjects, limitation of the parent reported HRQoL tool, or subject genotype variability. Alternative designed trials and more study subjects with PCD will be needed to validate important observations from this work.
•For patients with PCD, an overall trend of lactate reduction with time on triheptanoin was noted.•Parent reported HRQoL assessments with triheptanoin treatment showed mixed results.•Subjects with buried amino acids in the pyruvate carboxyltransferase domain of PC that undergo destabilizing replacements may be more likely to respond to triheptanoin.•Alternative designed trials and more study subjects with PCD are needed to validate important observations from this work.
ITSN1 plays an important role in brain development. Recent studies in large cohorts of subjects with neurodevelopmental disorders have identified de novo variants in ITSN1 gene thereby suggesting ...that this gene is involved in the development of such disorders. The aim of this study is to provide further proof of such a link. We performed trio exome sequencing in a patient presenting autism, intellectual disability, and severe behavioral difficulties. Additional affected patients with a neurodevelopmental disorder harboring a heterozygous variant in ITSN1 (NM_003024.2) were collected through a worldwide collaboration. All patients underwent detailed phenotypic and genetic assessment and data was collected and shared by healthcare givers. We identified ten novel patients from eight families with heterozygous truncating or missense variants in ITSN1 gene. In addition, four previously published patients from large meta-analysis studies were included. In total, 7/14 patients presented a de novo variant in ITSN1. All patients showed neurodevelopmental disorders from autism spectrum disorders (90%), intellectual disability (86%), and epilepsy (30%). We demonstrated that truncating variants are in the first half of ITSN1 whereas missense variants are clustered in C-terminal region. We suggest ITSN1 gene is involved in development of an autism spectrum disorder with variable additional neurodevelopmental deficiency, thus confirming the hypothesis that ITSN1 is important for brain development.
The human chromosome 19q13.11 deletion syndrome is associated with a variable phenotype that includes aplasia cutis congenita (ACC) and ectrodactyly as specific features. UBA2 (ubiquitin-like ...modifier-activating enzyme 2) lies adjacent to the minimal deletion overlap region. We aimed to define the UBA2-related phenotypic spectrum in humans and zebrafish due to sequence variants and to establish the mechanism of disease.
Exome sequencing was used to detect UBA2 sequence variants in 16 subjects in 7 unrelated families. uba2 loss of function was modeled in zebrafish. Effects of human missense variants were assessed in zebrafish rescue experiments.
Seven human UBA2 loss-of-function and missense sequence variants were detected. UBA2-phenotypes included ACC, ectrodactyly, neurodevelopmental abnormalities, ectodermal, skeletal, craniofacial, cardiac, renal, and genital anomalies. uba2 was expressed in zebrafish eye, brain, and pectoral fins; uba2-null fish showed deficient growth, microcephaly, microphthalmia, mandibular hypoplasia, and abnormal fins. uba2-mRNAs with human missense variants failed to rescue nullizygous zebrafish phenotypes.
UBA2 variants cause a recognizable syndrome with a wide phenotypic spectrum. Our data suggest that loss of UBA2 function underlies the human UBA2 monogenic disorder and highlights the importance of SUMOylation in the development of affected tissues.
Key Clinical Message
We report two, genotypically identical but phenotypically distinct cases of Schaaf‐Yang syndrome and propose the early use of Genome Sequencing in patients with nonspecific ...presentations to facilitate the early diagnosis of children with rare genetic diseases and improve overall health care outcomes.
Background:
Wilson disease (WD) and glucose transporter type 1 (GLUT1) deficiency syndrome are two syndromes with different modes of inheritance but share certain similarities on neurological ...presentation. To date we have not found previous reports of an association between these two disorders.
Case Presentation:
Here we describe a 9-year-old male with global developmental delay that presented with intermittent and sudden onset weakness that first occurred at age 3. He was diagnosed with a mutation in the
SLC2A1
(Solute Carrier Family 2 Member 1) gene, which results in GLUT1 deficiency. A ketogenic diet could not be started because of unexplained elevated liver enzymes. Due to his liver enzymes' persistent elevation, further investigations demonstrated mildly decreased ceruloplasmin levels, high basal 24-h urinary copper excretion, and an elevated hepatic parenchymal copper concentration on liver biopsy, consistent with WD. Genetic testing revealed two separate mutations in the
ATP7B
(ATPase Copper Transporting Beta) gene, consistent with WD. The patient was treated with a low copper diet, zinc acetate, and trientine hydrochloride. When liver enzymes normalized, he was subsequently started on a ketogenic diet with improvement in neurological symptoms. His neurological symptoms were most likely secondary to GLUT1 deficiency syndrome, as WD's neurological symptoms are primarily observed in the second decade of life.
Conclusion:
Recent studies have demonstrated the importance of genetic testing upon unexplained persistent elevation of liver enzymes. This case highlights the importance of carefully evaluating a patient with an unexplained liver disorder, even in the presence of primary neurological disease, as it can have significant therapeutic implications.
We report two siblings with intractable epilepsy, developmental regression, and progressive cerebellar atrophy due to biallelic variants in the gene CAD. For the affected girl, uridine started at age ...5 resulted in dramatic improvements in seizure control and development, cessation of cerebellar atrophy, and resolution of hematological abnormalities. Her older brother had a more severe course and only modest response to uridine started at 14 years old. Treatment of this progressive condition via uridine supplementation provides an example of precision diagnosis and treatment using clear outcome measures and biomarkers to monitor efficacy.
Objectives : The main objective of the study is to characterize the effects of genetic abnormalities/syndromes (GA/S) on perioperative outcomes of cardiac surgeries involving repair of conotruncal ...heart defects (CTHD).
Design : The study involves a single-center retrospective analysis of patients who underwent complete repair of CTHDs (tetralogy of Fallot TOF, truncus arteriosus, interrupted aortic arch, and ventricular septal defect with coarctation) between January 2000 and December 2015. The primary outcome was the post operative length of stay (PLOS). The secondary outcomes were mortality, cardiac complications, hematologic complications, infections, and number of medications-at-discharge.
Setting : Cardiac intensive care unit in a tertiary pediatric hospital in South Florida that performs around 300 open-heart surgeries a year.
Subjects : A total of 177 patients with CTHDs who underwent cardiac surgeries in the stated time period were included in the final study cohort.
Measurements and Main Results :Majority of patients had TOF (72.5%) and 46 (26%) had GA/S. The most common GA/S was 22q11 deletion (37%). PLOS was significantly increased in patients with GA/S (P < 0.05). Patients with GA/S were 4.5 times more likely to have a postoperative cardiac complication, 4.2 times more likely to have a postoperative infection, and received 1.6 times more medications at discharge than those without GA/S. However, GA/S was not associated with increased perioperative mortality. Black patients were three times more likely to have a longer PLOS than White patients.
Conclusions : Perioperative outcomes in patients with GA/S suggested an increased residual cardiovascular disease and increased resource usage. Notably, this is the first study demonstrating the effect of race and ethnicity on PLOS in CTHD patients.
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