Newborn screening for common genetic variants associated with permanent hearing loss: Implementation in Ontario and a review of the first 3 years.

Purpose: Universal newborn hearing screening (UNHS) programs using audiometric techniques alone are limited in ability to detect non-congenital childhood permanent hearing loss (PHL). In 2019, Ontario launched universal newborn screening (NBS) for PHL risk factors: congenital cytomegalovirus (cCMV) and 22 common variants in GJB2 and SLC26A4. Here we describe our experience with genetic risk factor screening.

Multi-year enzyme expression in patients with mucopolysaccharidosis type VI after liver-directed gene therapy.

Background: Mucopolysaccharidosis type VI (MPS VI) is due to a deficiency of the lysosomal enzyme arylsulfatase B (ARSB) that results in multi-organ accumulation of glycosaminoglycans (GAGs). Limitations of current treatments prompted the development of a liver-directed gene therapy clinical trial for MPS VI.

Methods: We report the long-term follow-up of patients with MPS VI who discontinued enzyme replacement therapy (ERT) and received a single intravenous infusion of high-dose (6 × 10 genome copies/kg) recombinant adeno-associated virus serotype 8 (AAV8) vector expressing ARSB under the control of a liver-specific promoter (ClinicalTrials.

Severe Developmental Delay and Behavior Abnormalities in a Patient with De Novo CAMK2B Mutation: A Case Report and Literature Review.

The calcium/calmodulin-dependent protein kinase II-beta ( CAMK2B ) gene is important for calcium signaling and glutamatergic synapses, which impacts neuroplasticity and learning. Mutations in the CAMK2B gene, which cause autosomal dominant mental retardation 54 (Online Mendelian Inheritance in Man # 617799), can have multisystemic clinical impact. Due to the rarity of CAMK2B mutations at present, case reports about patients with CAMK2B mutations are limited.

Dual diagnosis of trisomy 21 and lethal perinatal Gaucher disease as a cause of non-immune hydrops fetalis in a twin pregnancy for a consanguineous couple.

Non-immune hydrops is a prenatal finding which can occur due to an underlying genetic diagnosis such as common chromosomal aneuploidy (Trisomy 21, Turner syndrome etc.). It is extremely rare to have more than one genetic cause of hydrops fetalis in a single pregnancy.

Liver-Directed Adeno-Associated Virus-Mediated Gene Therapy for Mucopolysaccharidosis Type VI.

BACKGROUND: Mucopolysaccharidosis type VI (MPS VI) is an inherited multisystem lysosomal disorder due to arylsulfatase B (ARSB) deficiency that leads to widespread accumulation of glycosaminoglycans (GAG), which are excreted in increased amounts in urine. MPS VI is characterized by progressive dysostosis multiplex, connective tissue and cardiac involvement, and hepatosplenomegaly. Enzyme replacement therapy (ERT) is available but requires life-long and costly intravenous infusions; moreover, it has limited efficacy on diseased skeleton and cardiac valves, compromised pulmonary function, and corneal opacities.

Two cases of carbonic anhydrase VA deficiency-An ultrarare metabolic decompensation syndrome presenting with hyperammonemia, lactic acidosis, ketonuria, and good clinical outcome.

The combination of neonatal hyperammonemia, lactic acidosis, ketonuria, and hypoglycemia is pathognomonic for carbonic anhydrase VA (CA-VA) deficiency. We present two cases of this rare inborn error of metabolism. Both newborns with South Asian ancestry presented with a metabolic decompensation characterized by hyperammonemia, lactic acidosis and ketonuria; one also had hypoglycemia.

A novel homozygous variant in REN in a family presenting with classic features of disorders involving the renin-angiotensin pathway, without renal tubular dysgenesis.

Autosomal recessively inherited pathogenic variants in genes associated with the renin-angiotensin-aldosterone system (RAAS) result in early onset oligohydramnios and clinical features of the Potter sequence, typically in association with proximal renal tubules dysgenesis. We describe two siblings and a first cousin who had severe oligohydramnios in the second trimester, and presented at birth with loose skin, wide fontanelles and sutures, and pulmonary insufficiency. Two had refractory hypotension during their brief lives and one received palliative care after birth.

Magnetic resonance imaging in the diagnosis of white matter signal abnormalities.

Background White matter abnormalities (WMAs) pose a diagnostic challenge when trying to establish etiologic diagnoses. During childhood and adult years, genetic disorders, metabolic disorders and acquired conditions are included in differential diagnoses. To assist clinicians and radiologists, a structured algorithm using cranial magnetic resonance imaging (MRI) has been recommended to aid in establishing working diagnoses that facilitate appropriate biochemical and genetic investigations.

Psychosocial impact on mothers receiving expanded newborn screening results.

Expanded newborn screening (NBS) for genetic disorders has improved diagnosis of numerous treatable diseases, positively impacting children's health outcomes. However, research about the psychological impact of expanded NBS on families, especially mothers, has been mixed. Our study examined associations between maternal experiences of expanded NBS and subsequent psychosocial functioning and parenting stress in mothers whose infants received either true negative (TN), true positive (TP) or false positive (FP) results after a 4- to 6-month period.

Rapid and Efficient Stable Gene Transfer to Mesenchymal Stromal Cells Using a Modified Foamy Virus Vector.

Mesenchymal stromal cells (MSCs) hold great promise for regenerative medicine. Stable ex vivo gene transfer to MSCs could improve the outcome and scope of MSC therapy, but current vectors require multiple rounds of transduction, involve genotoxic viral promoters and/or the addition of cytotoxic cationic polymers in order to achieve efficient transduction. We describe a self-inactivating foamy virus vector (FVV), incorporating the simian macaque foamy virus envelope and using physiological promoters, which efficiently transduces murine MSCs (mMSCs) in a single-round.

Incidence of medium-chain acyl-CoA dehydrogenase deficiency in Canada using the Canadian Paediatric Surveillance Program: Role of newborn screening.

Background: The incidence of medium-chain acyl-CoA dehydrogenase deficiency (MCADD) was estimated using the Canadian Paediatric Surveillance Program (CPSP) in Canada over a three-year period. Data regarding mutations associated with MCADD cases were collected wherever available.

Methods: Data were collected over a 36-month period using a monthly mailed questionnaire distributed through the CPSP to more than 2500 Canadian paediatricians, medical geneticists and paediatric pathologists.

Methylenetetrahydrofolate reductase (MTHFR) deficiency and infantile epilepsy.

Objectives: A recessively inherited defect leading to deficiency of the enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) underlies one form of hyperhomocysteinemia. We describe the association of severe MTHFR deficiency and neurological manifestations with particular attention to neurodevelopment and evolution of epileptic seizures.

Methods: Case study and review of literature.

Asymptomatic critical hypoglycaemia: a dangerous presentation of glycogen storage disease type Ib in infancy.

Unlabelled: We report the case of a 3-month-old boy who presented with a 3-day history of respiratory tract infection and poor feeding. He was incidentally found to have profound hypoglycaemia, high-anion-gap lactic acidosis, ketonuria, hyperlipidemia, hepatomegaly, growth failure and neutropenia. Glycogen storage disease type Ib (GSD Ib), an autosomal recessive metabolic defect of the microsomal transporter glucose-6-phosphate-translocase, was suspected and confirmed by genetic testing.