| 1. |
- Rogers, Amanda, et al.
(författare)
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De novo KCNA1 variants in the PVP motif cause infantile epileptic encephalopathy and cognitive impairment similar to recurrent KCNA2 variants
- 2018
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Ingår i: American Journal of Medical Genetics. Part A. - : John Wiley & Sons. - 1552-4825 .- 1552-4833. ; 176:8, s. 1748-1752
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Tidskriftsartikel (refereegranskat)abstract
- Derangements in voltage-gated potassium channel function are responsible for a range of paroxysmal neurologic disorders. Pathogenic variants in the KCNA1 gene, which encodes the voltage-gated potassium channel Kv1.1, are responsible for Episodic Ataxia Type 1 (EA1). Patients with EA1 have an increased incidence of epilepsy, but KCNA1 variants have not been described in epileptic encephalopathy. Here, we describe four patients with infantile-onset epilepsy and cognitive impairment who harbor de novo KCNA1 variants located within the Kv-specific Pro-Val-Pro (PVP) motif which is essential for channel gating. The first two patients have KCNA1 variants resulting in (p.Pro405Ser) and (p.Pro405Leu), respectively, and a set of identical twins has a variant affecting a nearby residue (p.Pro403Ser). Notably, recurrent de novo variants in the paralogous PVP motif of KCNA2 have previously been shown to abolish channel function and also cause early-onset epileptic encephalopathy. Importantly, this report extends the range of phenotypes associated with KCNA1 variants to include epileptic encephalopathy when the PVP motif is involved.
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| 2. |
- Strang-Karlsson, Sonja, et al.
(författare)
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A novel compound heterozygous mutation in the POMK gene causing limb-girdle muscular dystrophy-dystroglycanopathy in a sib pair
- 2018
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Ingår i: Neuromuscular Disorders. - : Elsevier BV. - 0960-8966 .- 1873-2364. ; 28:7, s. 614-618
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Tidskriftsartikel (refereegranskat)abstract
- We describe two Finnish siblings in whom an incidentally detected elevated creatine kinase activity eventually led to a diagnosis of limb-girdle muscular dystrophy-dystroglycanopathy (Type C12; MDDGC12). When diagnosed at age 10 and 13 years, they were mildly affected with a slow or non-progressive disease course. The main symptoms comprised infrequent hip cramps triggered by flexion, neck cramps triggered by yawning, transient growing pains, calf hypertrophy and mild proximal muscle weakness. Their cognitive and motor developments were unremarkable and they were physically active. Whole-exome sequencing revealed compound heterozygous mutations, both of which were novel, in the protein O-mannosyl kinase (POMK) gene in both siblings; a missense mutation, p.Pro322Leu (c.965C > T), and a nonsense mutation, p.Arg46Ter (c.136C > T). The results were confirmed by Sanger sequencing, showing that the parents were heterozygous carriers of one mutation each. This report adds to the literature by providing phenotype and genotype data on this ultra-rare POMK-related dystroglycanopathy.
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| 3. |
- Yates, T. Michael, et al.
(författare)
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SLC35A2-related congenital disorder of glycosylation : Defining the phenotype
- 2018
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Ingår i: European journal of paediatric neurology. - : ELSEVIER SCI LTD. - 1090-3798 .- 1532-2130. ; 22:6, s. 1095-1102
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Tidskriftsartikel (refereegranskat)abstract
- We aim to further delineate the phenotype associated with pathogenic variants in the SLC35A2 gene, and review all published literature to-date. This gene is located on the X chromosome and encodes a UDP-galactose transporter. Pathogenic variants in SLC35A2 cause a congenital disorder of glycosylation. The condition is rare, and less than twenty patients have been reported to-date. The phenotype is complex and has not been fully defined. Here, we present a series of five patients with de novo pathogenic variants in SLC35A2. The patients' phenotype includes developmental and epileptic encephalopathy with hypsarrhythmia, facial dysmorphism, severe intellectual disability, skeletal abnormalities, congenital cardiac disease and cortical visual impairment. Developmental and epileptic encephalopathy with hypsarrhythmia is present in most patients with SLC35A2 variants, and is drug-resistant in the majority of cases. Adrenocorticotropic hormone therapy may achieve partial or complete remission of seizures, but the effect is usually temporary. Isoelectric focusing of transferrins may be normal after infancy, therefore a congenital disorder of glycosylation should still be considered as a diagnosis in the presence of a suggestive phenotype. We also provide evidence that cortical visual impairment is part of the phenotypic spectrum.
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