Early onset or syndromic epilepsy

Gene: SLC9A6

Green List (high evidence)

X-linked dominant syndromic mental retardation (Christianson type). Along with other features see early onset seizures of variable types.Christianson et al 1999, 5 generation S African family - 16 affected males, 10 carrier females - 87.5% of the males had grand mal seizures. Gilfillan et al, 2008 - 3 additional families epilepsy occured between 9 & 26 months. SLC9A6 variants were identified in all 4 of these families. Schroer et al, 2010 - large family with 6 affected males - all had onset of seizures by 2 years - nonsense variant detected. Pescosolido et al, 2014 - 14 boys from 12 unrelated families (one family prev reported by Schroer) - all patients early onset of variable seizures.

Created: 6 Aug 2019, 8:31 p.m. | Last Modified: 6 Aug 2019, 8:31 p.m.

Panel Version: 1.188

Mode of inheritance
X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)

Phenotypes
Mental retardation, X-linked syndromic, Christianson type, 300243

Publications

• 20395263
• 24123876

I don't know

Review and rating collated by Tracy Lester (Oxford Medical Genetics Laboratories Oxford University Hospitals NHS Foundation Trust, 2019_02_06) on behalf of Wessex and West Midlands GLH for GMS Neurology specialist test group, for Clinical Indication R59 'Early onset or syndromic epilepsy'. Review contributors: John Taylor and Helen Lord. Suggested gene rating: Green.

Created: 6 Aug 2019, 8:38 p.m. | Last Modified: 6 Aug 2019, 8:38 p.m.

Panel Version: 1.189

Comment on mode of inheritance: Comment on mode of inheritance: Changed the MOI from XLR to XLD based on Pescosolido et al., 2014 (PMID:25044251) who report some symptoms (mild to moderate ID) in heterozygous female carriers. Note that NHE6 is an alias for SLC9A6. Although Gene2Phenotype list a hemizygous inheritance for 'MENTAL RETARDATION SYNDROMIC X-LINKED CHRISTIANSON TYPE' OMIM record an XLD inheritance for MIM:300243.

Created: 18 Jul 2019, 10:30 a.m. | Last Modified: 18 Jul 2019, 10:30 a.m.

Panel Version: 1.168

Green List (high evidence)

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Phenotypes
Mental retardation, X-linked syndromic, Christianson type

Publications

• Gilfillan et al (2008) Am J Hum Genet 82: 1003_1010

Variants in this GENE are reported as part of current diagnostic practice

Green List (high evidence)

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Phenotypes
Mental retardation, X-linked syndromic, Christianson type

Publications

• Gilfillan et al (2008) Am J Hum Genet 82: 1003_1010

Variants in this GENE are reported as part of current diagnostic practice

Green List (high evidence)

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Phenotypes
Mental retardation, X-linked syndromic, Christianson type

Publications

• Gilfillan et al (2008) Am J Hum Genet 82: 1003_1010

Variants in this GENE are reported as part of current diagnostic practice

Green List (high evidence)

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Phenotypes
Mental retardation, X-linked syndromic, Christianson type

Publications

• Gilfillan et al (2008) Am J Hum Genet 82: 1003 1010

Variants in this GENE are reported as part of current diagnostic practice

Comment on mode of inheritance: Confirmed with reviewer biallelic in females.

Created: 29 Jan 2016, 5:26 p.m.