Intellectual disability - microarray and sequencing
Gene: FRRS1L Amber List (moderate evidence)I don't know
I can only see that developmental problems occur after the onset of seizures, therefore this gene may be better addressed via the EIEE route. This is green on the genetic epilepsy syndromes panel already. This decision can be reviewed in light of the scope of the ID panel, as needed.Created: 19 Jul 2019, 11:44 a.m. | Last Modified: 19 Jul 2019, 11:44 a.m.
Panel Version: 0.203
Comment on list classification: FRRS1L identified in literature PMID:30914295 as missing in PanelApp compared to other curated gene list for ID genes.
FRRS1L was added to the ID panel and rated Green by Konstantinos Varvagiannis. Several individuals homozygous for LoF variants have been reported by Madeo et al. (PMID:27236917) and Shaheen et al. (PMID:27239025 - 2 individuals of this family previously published in 21147040). Phenotype is relevant for inclusion in ID panel and FRRS1L is probable in Gene2Phenotype although no phenotypes have been assigned to the G2P entry.Created: 20 May 2019, 4:14 p.m.
Green List (high evidence)
Biallelic pathogenic variants in FRRS1L cause Epileptic encephalopathy, early infantile, 37 (EIEE37 - MIM 616981).
Several individuals homozygous for LoF variants have been reported by Madeo et al. (PMID:27236917) and Shaheen et al. (PMID:27239025 - 2 individuals of this family previously published in 21147040). DD and choreoathetotic movement disorder may precede onset of seizures and subsequent regression. Intellectual disability was a universal feature.
Both articles and the respective phenotype are summarized in OMIM.
Extensive functional studies have been performed in the article by Madeo et al. as well as in PMID: 29276473 (Han et al.) and suggest a role in glutamatergic transmission.
FRRS1L is included in the DD panel of G2P, associated with Epileptic encephalopathy with continuous spike-and-wave during sleep.
This gene is included in gene panels for ID offered by several diagnostic laboratories (incl. Radboudumc).
As a result, this gene can be considered for inclusion in the ID panel as green, if the phenotype of EIEE is thought to be relevant.
Sources: Literature, Radboud University Medical Center, NijmegenCreated: 19 Dec 2018, 12:45 p.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Epileptic encephalopathy, early infantile, 37 (MIM 616981)
Publications
Variants in this GENE are reported as part of current diagnostic practice
Source Expert Review Amber was added to FRRS1L. Added phenotypes Epileptic encephalopathy, early infantile, 37, 616981 for gene: FRRS1L Publications for gene FRRS1L were changed from 27236917; 27239025; 21147040; 29276473 to 29276473; 27239025; 21147040; 27236917; 30914295 Rating Changed from No List (delete) to Amber List (moderate evidence)
gene: FRRS1L was added gene: FRRS1L was added to Intellectual disability. Sources: Literature,Radboud University Medical Center, Nijmegen Mode of inheritance for gene: FRRS1L was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: FRRS1L were set to 27236917; 27239025; 21147040; 29276473 Phenotypes for gene: FRRS1L were set to Epileptic encephalopathy, early infantile, 37 (MIM 616981) Penetrance for gene: FRRS1L were set to Complete Review for gene: FRRS1L was set to GREEN gene: FRRS1L was marked as current diagnostic
If promoting or demoting a gene, please provide comments to justify a decision to move it.
Genes included in a Genomics England gene panel for a rare disease category (green list) should fit the criteria A-E outlined below.
These guidelines were developed as a combination of the ClinGen DEFINITIVE evidence for a causal role of the gene in the disease(a), and the Developmental Disorder Genotype-Phenotype (DDG2P) CONFIRMED DD Gene evidence level(b) (please see the original references provided below for full details). These help provide a guideline for expert reviewers when assessing whether a gene should be on the green or the red list of a panel.
A. There are plausible disease-causing mutations(i) within, affecting or encompassing an interpretable functional region(ii) of this gene identified in multiple (>3) unrelated cases/families with the phenotype(iii).
OR
B. There are plausible disease-causing mutations(i) within, affecting or encompassing cis-regulatory elements convincingly affecting the expression of a single gene identified in multiple (>3) unrelated cases/families with the phenotype(iii).
OR
C. As definitions A or B but in 2 or 3 unrelated cases/families with the phenotype, with the addition of convincing bioinformatic or functional evidence of causation e.g. known inborn error of metabolism with mutation in orthologous gene which is known to have the relevant deficient enzymatic activity in other species; existence of an animal model which recapitulates the human phenotype.
AND
D. Evidence indicates that disease-causing mutations follow a Mendelian pattern of causation appropriate for reporting in a diagnostic setting(iv).
AND
E. No convincing evidence exists or has emerged that contradicts the role of the gene in the specified phenotype.
(i)Plausible disease-causing mutations: Recurrent de novo mutations convincingly affecting gene function. Rare, fully-penetrant mutations - relevant genotype never, or very rarely, seen in controls. (ii) Interpretable functional region: ORF in protein coding genes miRNA stem or loop. (iii) Phenotype: the rare disease category, as described in the eligibility statement. (iv) Intermediate penetrance genes should not be included.
It’s assumed that loss-of-function variants in this gene can cause the disease/phenotype unless an exception to this rule is known. We would like to collect information regarding exceptions. An example exception is the PCSK9 gene, where loss-of-function variants are not relevant for a hypercholesterolemia phenotype as they are associated with increased LDL-cholesterol uptake via LDLR (PMID: 25911073).
If a curated set of known-pathogenic variants is available for this gene-phenotype, please contact us at [email protected]
We classify loss-of-function variants as those with the following Sequence Ontology (SO) terms:
Term descriptions can be found on the PanelApp homepage and Ensembl.
If you are submitting this evaluation on behalf of a clinical laboratory please indicate whether you report variants in this gene as part of your current diagnostic practice by checking the box
Standardised terms were used to represent the gene-disease mode of inheritance, and were mapped to commonly used terms from the different sources. Below each of the terms is described, along with the equivalent commonly-used terms.
A variant on one allele of this gene can cause the disease, and imprinting has not been implicated.
A variant on the paternally-inherited allele of this gene can cause the disease, if the alternate allele is imprinted (function muted).
A variant on the maternally-inherited allele of this gene can cause the disease, if the alternate allele is imprinted (function muted).
A variant on one allele of this gene can cause the disease. This is the default used for autosomal dominant mode of inheritance where no knowledge of the imprinting status of the gene required to cause the disease is known. Mapped to the following commonly used terms from different sources: autosomal dominant, dominant, AD, DOMINANT.
A variant on both alleles of this gene is required to cause the disease. Mapped to the following commonly used terms from different sources: autosomal recessive, recessive, AR, RECESSIVE.
The disease can be caused by a variant on one or both alleles of this gene. Mapped to the following commonly used terms from different sources: autosomal recessive or autosomal dominant, recessive or dominant, AR/AD, AD/AR, DOMINANT/RECESSIVE, RECESSIVE/DOMINANT.
A variant on one allele of this gene can cause the disease, however a variant on both alleles of this gene can result in a more severe form of the disease/phenotype.
A variant in this gene can cause the disease in males as they have one X-chromosome allele, whereas a variant on both X-chromosome alleles is required to cause the disease in females. Mapped to the following commonly used term from different sources: X-linked recessive.
A variant in this gene can cause the disease in males as they have one X-chromosome allele. A variant on one allele of this gene may also cause the disease in females, though the disease/phenotype may be less severe and may have a later-onset than is seen in males. X-linked inactivation and mosaicism in different tissues complicate whether a female presents with the disease, and can change over their lifetime. This term is the default setting used for X-linked genes, where it is not known definitately whether females require a variant on each allele of this gene in order to be affected. Mapped to the following commonly used terms from different sources: X-linked dominant, x-linked, X-LINKED, X-linked.
The gene is in the mitochondrial genome and variants within this can cause this disease, maternally inherited. Mapped to the following commonly used term from different sources: Mitochondrial.
Mapped to the following commonly used terms from different sources: Unknown, NA, information not provided.
For example, if the mode of inheritance is digenic, please indicate this in the comments and which other gene is involved.