scholarly journals The neonatal SCN2A mutant channel mimics adult channel properties

2020 ◽  
Vol 152 (5) ◽  
Author(s):  
Grace K. Muller
Keyword(s):  
Early Onset ◽  
Mutant Channel ◽  
Channel Properties

SCN2A mutations can cause early-onset epilepsy. Thompson et al. examined these human mutations in neonatal versus adult channel isoforms.

Mechanism of Increased Open Probability by a Mutation of the BK Channel

2006 ◽  
Vol 96 (3) ◽  
pp. 1507-1516 ◽  
Author(s):  
Ana Díez-Sampedro ◽  
William R. Silverman ◽  
Jocelyn F. Bautista ◽  
George B. Richerson
Keyword(s):  
Bk Channel ◽  
Single Channels ◽  
Voltage Sensitivity ◽  
Wild Type ◽  
Open Probability ◽  
Mutant Channel ◽  
Α Subunit ◽  
Brain Excitability ◽  
The Difference ◽  
Channel Properties

A missense mutation (D434G) has recently been identified in the α subunit of the human large-conductance calcium-activated potassium (BK) channel. Interestingly, although the mutation causes an increase in open probability, individuals that carry the mutation have epilepsy and/or paroxysmal dyskinesia, disorders of increased brain excitability. To define the mechanisms of the mutation, we have used recordings from single channels and measurement of macroscopic conductances to examine the gating of the α subunit, modulation by the regulatory β4 subunit, and the effect of Mg2+ on channel properties. Although there was relatively little difference in open dwell times for the mutant and wild-type α subunits, the mutant channel spent less time in a long-lived closed state. Co-expression of the β4 subunit caused the wild-type channel to be less sensitive to calcium at low Ca2+ concentrations but had little effect on the mutant channel, further accentuating the difference between the wild-type and the mutant channels. In the absence of Ca2+, there was no difference in Mg2+ or voltage sensitivity of the mutant and wild-type channels, whereas in 2 mM Ca2+, the mutant channel had greater open probability at every Mg2+ concentration tested. We conclude that the D434G mutation modifies Ca2+-dependent activation, but we find no evidence of a direct effect on activation by Mg2+ or voltage. The resulting enhancement of BK channel function leads to an increase in brain excitability, possibly due to more rapid repolarization of action potentials.

Association of vitamin D receptor genotypes with early onset rheumatoid arthritis

2001 ◽  
Vol 28 (1) ◽  
pp. 89-93 ◽  
Author(s):  
J. R. Garcia-Lozano ◽  
M. F. Gonzalez-Escribano ◽  
A. Valenzuela ◽  
A. Garcia ◽  
A. Nunez-Roldan
Keyword(s):  
Rheumatoid Arthritis ◽  
Vitamin D ◽  
Vitamin D Receptor ◽  
Early Onset

Outcome of infants with unilateral Sturge-Weber syndrome and early onset seizures

2000 ◽  
Vol 42 (11) ◽  
pp. 756-759 ◽  
Author(s):  
Uri Kramer ◽  
Esther Kahana ◽  
Zamir Shorer ◽  
Bruria Ben-Zeev
Keyword(s):  
Early Onset ◽  
Weber Syndrome ◽  
Sturge Weber Syndrome

Neuropsychological Deficits in the Prodromal Phase and Course of an Early-Onset Schizophrenia

2014 ◽  
Vol 42 (3) ◽  
pp. 167-176 ◽  
Author(s):  
Vanessa Puetz ◽  
Thomas Günther ◽  
Berrak Kahraman-Lanzerath ◽  
Beate Herpertz-Dahlmann ◽  
Kerstin Konrad
Keyword(s):  
Verbal Memory ◽  
Early Onset ◽  
Neuropsychological Functioning ◽  
Neuropsychological Testing ◽  
Clinical Situation ◽  
Adolescent Male ◽  
Antipsychotic Treatment ◽  
Early Onset Schizophrenia ◽  
Prodromal Phase ◽  
Illness Onset

Objectives: Although clear advances have been achieved in the study of early-onset schizophrenia (EOS), little is known to date about premorbid and prodromal neuropsychological functioning in EOS. Method: Here, we report on a case of an adolescent male with EOS who underwent neuropsychological testing before and after illness onset. Results: Marked cognitive deficits in the domains of attention, set-shifting, and verbal memory were present both pre-onset and during the course of schizophrenia, though only deficits in verbal memory persisted after illness-onset and antipsychotic treatment. Conclusion: The findings of this case study suggest that impairments in the verbal memory domain are particularly prominent symptoms of cognitive impairment in prodromal EOS and persist in the course of the disorder, which further demonstrates the difficult clinical situation of adequate schooling opportunities for adolescent patients with EOS.

Early-onset anorexia.

1992 ◽  
Author(s):  
B. Lask ◽  
R. Bryant-Waugh
Keyword(s):  
Early Onset
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