Severe microcephaly
Gene: TRAPPC12The rating of this gene has been updated following NHS Genomic Medicine Service approval.Created: 10 Mar 2022, 10:52 a.m. | Last Modified: 10 Mar 2022, 10:52 a.m.
Panel Version: 2.282
Comment on list classification: There is enough evidence to rate this gene Green at the next GMS panel update (added 'for-review' tag) - sufficient unrelated published cases, plus an internally diagnosed individual; where measurements were indicated (3/5 cases), microcephaly was of relevant severity to this panel (<−3 SD)Created: 20 Jan 2021, 5:16 p.m. | Last Modified: 20 Jan 2021, 5:16 p.m.
Panel Version: 2.73
- PMID: 28777934 (2017) - Three individuals from two unrelated families with severe GDD, seizures, hearing loss, microcephaly, and structural brain abnormalities including ventriculomegaly, pons hypoplasia, agenesis of the corpus callosum and brain atrophy.
Exome sequencing revealed different biallelic TRAPPC12 variants in both families. Patient-derived fibroblasts showed fragmentation of the Golgi, abnormal Golgi trafficking and delays in mitosis.
- PMID: 32369837 (2020) - Two unrelated patients with severe neurodevelopmental delay and brain atrophy, and different homozygous variants in this gene. One individual also presented epilepsy and microcephaly (-5.72 SD).
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Copied from Intellectual disability panel review by Louise Daugherty (Genomics England Curator), 1 Jul 2019:
"in addition to this published evidence, recently a diagnosis of TRAPPC12 from an exome has been discovered (pers. comm Genomics England clinical team), however the case had a negative 100K Genomes Project report, as there was not enough evidence to make the gene Green at the time. The child had developmental delay, microcephaly and cerebellar hypoplasia"Created: 20 Jan 2021, 5:11 p.m. | Last Modified: 20 Jan 2021, 5:11 p.m.
Panel Version: 2.72
Phenotypes
Encephalopathy, progressive, early-onset, with brain atrophy and spasticity, OMIM:617669; Early-onset progressive encephalopathy-hearing loss-pons hypoplasia-brain atrophy syndrome, MONDO:0044696
Publications
Four families reported with a severe progressive encephalopathy characterized by microcephaly, global developmental delay, and hearing loss.
Sources: Expert listCreated: 4 Sep 2020, 2:32 a.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Encephalopathy, progressive, early-onset, with brain atrophy and spasticity, MIM# 617669
Publications
Variants in this GENE are reported as part of current diagnostic practice
Tag for-review was removed from gene: TRAPPC12.
Source Expert Review Green was added to TRAPPC12. Rating Changed from Amber List (moderate evidence) to Green List (high evidence)
Phenotypes for gene: TRAPPC12 were changed from Encephalopathy, progressive, early-onset, with brain atrophy and spasticity, MIM# 617669 to Encephalopathy, progressive, early-onset, with brain atrophy and spasticity, OMIM:617669; Early-onset progressive encephalopathy-hearing loss-pons hypoplasia-brain atrophy syndrome, MONDO:0044696
Gene: trappc12 has been classified as Amber List (Moderate Evidence).
Tag for-review tag was added to gene: TRAPPC12.
gene: TRAPPC12 was added gene: TRAPPC12 was added to Severe microcephaly. Sources: Expert list Mode of inheritance for gene: TRAPPC12 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: TRAPPC12 were set to 32369837; 28777934 Phenotypes for gene: TRAPPC12 were set to Encephalopathy, progressive, early-onset, with brain atrophy and spasticity, MIM# 617669 Review for gene: TRAPPC12 was set to GREEN gene: TRAPPC12 was marked as current diagnostic