Intellectual disability - microarray and sequencing
Gene: POLR3BThe mode of inheritance of this gene has been updated following NHS Genomic Medicine Service approval.Created: 14 Mar 2022, 2:22 p.m. | Last Modified: 14 Mar 2022, 2:22 p.m.
Panel Version: 3.1519
Comment on mode of inheritance: Both biallelic and monoallelic variants have been linked to ID. There is enough evidence for a Green rating for both allelic requirements, so POLR3B has been tagged Q2_21_MOI to change the MOI from biallelic to both biallelic/monoallelic at the next GMS review.
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Biallelic variants in POLR3B are a well-established cause of hypomyelinating leukodystrophy (OMIM:614381), associated with variable ID.
Recently, heterozygous variants were also linked to ID. Djordjevic et al. 2021 (PMID:33417887) identified different de novo POLR3B variants in 6 unrelated individuals. The majority had some degree of DD, with 5/6 participants being diagnosed with intellectual disability ranging from mild to moderate severity. Four individuals required assistance with basic activities of daily living, however none had developmental regression. Protein modelling and proteomic analysis shows variants caused aberrant association of individual enzyme subunits rather than affecting overall enzyme assembly or stability.Created: 16 Jun 2021, 1:23 p.m. | Last Modified: 16 Jun 2021, 1:23 p.m.
Panel Version: 3.1133
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
LEUKODYSTROPHY, HYPOMYELINATING, 8, WITH OR WITHOUT OLIGODONTIA AND/OR HYPOGONADOTROPIC HYPOGONADISM
Publications
This is a pertinent gene from the NIHR BioResource - Rare Diseases Study (NIHRBR-RD) BRIDGE Study : SPEED (Specialist Pathology: Evaluating Exomes in Diagnostics) which covers epilepsies, movement and microcephaly disorders, this gene is on the SPEED_NEURO_20170705 gene list. Evidences used for SPEED NEURO gene list: in_ddg2p_20141118_conf;in_ddg2p_20141118_conf;in_ddg2p_201507;in_ddg2p_201507_conf;in_ddg2p_2_4_2017;in_ddg2p_2_4_2017_conf;in_gilissen_2014_known . Main mutation mechanism : All missense/in frame; Loss of functionCreated: 27 Jul 2017, 8:06 p.m.
Evidences key, gene present in following gene lists and main mutation mechanism : ddg2p_20141118; ddg2p_20141118_conf; ddg2p_201507; ddg2p_201507_conf; find_uk10k; gilissen_2014_known; Nijmegen_ID_diagnostic; Nijmegen_ID_candidates; GEL_ID_green_20160217; neuro_20160418_strict; All missense/in frame; Loss of function. This is a pertinent gene from the BRIDGE Study : SPEED (Specialist Pathology: Evaluating Exomes in Diagnostics) which covers epilepsies, movement and microcephaly disorders, this gene comes from the SPEED_NEURO_v3.0_20170404 gene list. The following experts from the BRIDGE consortium NIHRBR-RD contributed to this panel: - Professor F. Lucy Raymond, Cambridge Institute for Medical Research, University of Cambridge - Manju Kurian, Paediatric neurologist, Great Ormond Street Hosptial - Keren Carss, NIHR BioResource - Rare Diseases, Cambridge University Hospitals NHS Foundation Trust - Alba Sanchis-Juan, NIHR BioResource - Rare Diseases, Cambridge University Hospitals NHS Foundation Trust - Marie Erwood NIHR BioResource - Rare Diseases, Cambridge University Hospitals NHS Foundation Trust - Louise Daugherty, NIHR BioResource - Rare Diseases, Cambridge University Hospitals NHS Foundation TrustCreated: 19 Jul 2017, 1:09 p.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Publications
Mode of pathogenicity
Mode of inheritance for gene: POLR3B was changed from X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males) to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Tag Q2_21_MOI was removed from gene: POLR3B.
Source NHS GMS was added to POLR3B. Mode of inheritance for gene POLR3B was changed from BIALLELIC, autosomal or pseudoautosomal to X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Publications for gene: POLR3B were set to
Mode of inheritance for gene: POLR3B was changed from BIALLELIC, autosomal or pseudoautosomal to BIALLELIC, autosomal or pseudoautosomal
Tag Q2_21_MOI tag was added to gene: POLR3B.
Phenotypes for gene: POLR3B were changed from Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism, OMIM:614381 to Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism, OMIM:614381; POLR3B-related neurodevelopmental disorder; Ataxia, spasticity, and demyelinating neuropathy
Phenotypes for gene: POLR3B were changed from Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropichypogonadism, 614381; LEUKODYSTROPHY, HYPOMYELINATING, 8, WITH OR WITHOUT OLIGODONTIA AND/OR HYPOGONADOTROPIC HYPOGONADISM to Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism, OMIM:614381
12.03.2018: Due to major updates completed (Phase 1, 2 and 3), this panel was promoted to Version 2 in order to reflect the major updates since November 2017 which have resulted in reviews for 836 genes added by Genomics England Curators and the Clinical Team, 130 new Green genes added to the interpretation pipeline (from 751 to 881 Green genes), and the gene total has increased from 1879 to 1927.
The Gel status was updated for this whole panel
The Gel status was updated for this whole panel
POLR3B was added to Intellectual disabilitypanel. Source: Expert Review Green Model of inheritance for gene POLR3B was set to BIALLELIC, autosomal or pseudoautosomal
POLR3B was added to Intellectual disabilitypanel. Sources: Radboud University Medical Center, Nijmegen