CNTNAP1 mutations cause CNS hypomyelination and neuropathy with or without arthrogryposis.

OBJECTIVE: To explore the phenotypic spectrum and pathophysiology of human disease deriving from mutations in the CNTNAP1 gene. METHODS: In a field study on consanguineous Palestinian families, we identified 3 patients carrying homozygous mutations in the CNTNAP1 gene using whole-exome sequencing. An unrelated Irish family was detected by screening the GENESIS database for further CNTNAP1 mutations. Neurophysiology, MRI, and nerve biopsy including electron microscopy were performed for deep phenotyping. RESULTS: We identified 3 novel CNTNAP1 mutations in 5 patients from 2 families: c.2015G>A:p.(Trp672*) in a homozygous state in family 1 and c.2011C>T:p.(Gln671*) in a compound heterozygous state with c.2290C>T:p.(Arg764Cys) in family 2. Affected patients suffered from a severe CNS disorder with hypomyelinating leukodystrophy and peripheral neuropathy of sensory-motor type. Arthrogryposis was present in 2 patients but absent in 3 patients. Brain MRI demonstrated severe hypomyelination and secondary cerebral and cerebellar atrophy as well as a mega cisterna magna and corpus callosum hypoplasia. Nerve biopsy revealed very distinct features with lack of transverse bands at the paranodes and widened paranodal junctional gaps. CONCLUSIONS: CNTNAP1 mutations have recently been linked to patients with arthrogryposis multiplex congenita. However, we show that arthrogryposis is not an obligate feature. CNTNAP1-related disorders are foremost severe hypomyelinating disorders of the CNS and the peripheral nervous system. The pathology is partly explained by the involvement of CNTNAP1 in the proper formation and preservation of paranodal junctions and partly by the assumed role of CNTNAP1 as a key regulator in the development of the cerebral cortex.

Systemic Bioavailability and Dose Proportionality of Omega-3 Administered in Free Fatty Acid Form Compared With Ethyl Ester Form: Results of a Phase 1 Study in Healthy Volunteers.

BACKGROUND: Omega-3 carboxylic acids (OM3-CA) contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in free fatty acid form. Per gram, OM3-CA includes approximately half as much EPA as icosapent ethyl (IPE), an ethyl ester formulation of EPA. OBJECTIVE: The study aim was to assess systemic EPA and EPA + DHA exposures and plasma lipid parameters following multiple OM3-CA or IPE doses under low-fat dietary conditions, and dose proportionality after OM3-CA administration. METHODS: In this phase 1, two-cohort, open-label study (N = 114), participants following the Therapeutic Lifestyle Changes diet received either OM3-CA 2 g once daily for 10 days then OM3-CA 4 g once daily for 10 days, or IPE 2 g twice daily for 20 days. Exposure was considered similar if the 90% confidence intervals (CIs) of geometric least-squares mean (LSM) ratios for key pharmacokinetic parameters were within 80-125%. RESULTS: Baseline-adjusted steady-state EPA exposure was similar after dosing with OM3-CA 4 g/day versus IPE 4 g/day (LSM ratio, area under the concentration-time curve from time 0 to 24 h: 93.9%; 90% CI 85.6, 103.0). Combined molar-equivalent EPA + DHA exposure was 30.6% higher following OM3-CA 4 g/day than IPE 4 g/day. EPA and DHA exposure increased approximately proportionally with OM3-CA dose (2-4 g/day). Changes from baseline in lipid parameters were similar in the two cohorts. CONCLUSION: EPA exposure from OM3-CA and IPE was similar under low-fat dietary conditions, despite OM3-CA containing only approximately half as much EPA as IPE. EPA and DHA exposure from OM3-CA increased proportionally with dose.

Hepatic coma culminating in severe brain damage in a child with a SCN1A mutation.

An 11 months old boy, developed liver failure after febrile status epilepticus while being treated with valproic acid for myoclonic epilepsy and recurrent partial and generalized seizures. The diagnosis of Alpers-Huttenlocher disease was considered. A muscle biopsy showed mitochondrial dysfunction. Mitochondrial DNA depletion was ruled out. Sequencing of the polymerase gamma gene (POLG1) did not detect any mutations. Sequencing of the alpha-1 subunit gene of the voltage-gated neuronal sodium channel (SCN1A) revealed a novel, de novo amino acid change p.Val 1637 Glu. This case expands the spectrum of clinical presentations related to mutations in SCN1A. We warn that children with SCN1A mutations may be at risk for developing liver failure following status epilepticus, due to mitochondrial dysfunction.