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Intellectual disability - microarray and sequencing v3.1561 DALRD3 Konstantinos Varvagiannis changed review comment from: Biallelic pathogenic DALRD3 variants cause ?Developmental and epileptic encephalopathy 86 (# 618910).

Lentini et al (2020 - PMID: 32427860) report 2 sibs born to first cousin parents, homozygous for a DALRD3 pathogenic variant.

Both exhibited hypotonia, severe global DD and epilepsy (onset of seizures at the age 6-7m, poorly controlled by AEDs in one) corresponding overall to an developmental and epileptic encephalopathy. The authors reported subtle dysmorphic features. Other findings included GI concerns (in both) with microcephaly, CHD or renal anomalies in the younger.

WES guided by autozygome analysis revealed homozygosity for a DALRD3 stopgain variant (NM_001009996.3:c.1251C>A/pTyr417*) with Sanger sequencing confirming status of the children and carrier state of the parents.

DALRD3 encodes DALR anticodon-binding domain-containing protein 3. A DALR

It's DALR anticodon-binding domain is similar to those found in arginyl-tRNA synthetases RARS1/2.

As the authors demonstrate, and (better) summarized in OMIM, its product is a tRNA-binding protein that interacts with METTL2 to facilitate 3-methylcytosine (m3C) modification - by METTL2 - at position 32 of the anticodon loop in specific arginine tRNAs, namely tRNA-Arg-UCU and tRNA-Arg-CCU. In particular, DALRD3 seems to serve as discrimination factor required for recognition of these specific tRNAs.

In addition to DALRD3, a DALR anticodon-binding domain is also found in arginyl-tRNA synthetases (the cytoplasmic RARS1, and mitochondrial RARS2).

Given the variant type observed, predicting truncation of the protein and/or NMD, in LCLs from the 2 sibs (and comparison with controls) the authors demonstrated that the levels of full-length DALRD3 were decreased in cell lysates, with severe reduction (/loss) of m3C modification of the specific arginine tRNAs, which was not observed for other tRNAs (eg. tRNA-Ser-UGA) or controls. These findings were suggestive of c.1251C>A / pTyr417* being a partial LoF allele.

As the authors discuss, defects in tRNA modification have been associated with numerous human - among others neurological and neurodevelopmental - disorders (cited PMID: 30529455, table 1 of this review summarizing these incl. ADAT3-, PUS3-, TRMT1- related NDDs, etc).

Consider inclusion in the current panel with amber rating.
Sources: Literature; to: Biallelic pathogenic DALRD3 variants cause ?Developmental and epileptic encephalopathy 86 (# 618910).

Lentini et al (2020 - PMID: 32427860) report 2 sibs born to first cousin parents, homozygous for a DALRD3 pathogenic variant.

Both exhibited hypotonia, severe global DD and epilepsy (onset of seizures at the age 6-7m, poorly controlled by AEDs in one) corresponding overall to an developmental and epileptic encephalopathy. The authors reported subtle dysmorphic features. Other findings included GI concerns (in both) with microcephaly, CHD or renal anomalies in the younger.

WES in both followed by autozygome analysis revealed homozygosity for a DALRD3 stopgain variant (NM_001009996.3:c.1251C>A/pTyr417*) with Sanger sequencing confirming status of the children and carrier state of the parents.

DALRD3 encodes DALR anticodon-binding domain-containing protein 3. A DALR

As the authors demonstrate, and (better) summarized in OMIM, its product is a tRNA-binding protein that interacts with METTL2 to facilitate 3-methylcytosine (m3C) modification - by METTL2 - at position 32 of the anticodon loop in specific arginine tRNAs, namely tRNA-Arg-UCU and tRNA-Arg-CCU. In particular, DALRD3 seems to serve as discrimination factor required for recognition of these specific tRNAs.

In addition to DALRD3, a DALR anticodon-binding domain is also found in arginyl-tRNA synthetases (the cytoplasmic RARS1, and mitochondrial RARS2).

Given the variant type observed, predicting truncation of the protein and/or NMD, in LCLs from the 2 sibs (and comparison with controls) the authors demonstrated that the levels of full-length DALRD3 were decreased in cell lysates, with severe reduction (/loss) of m3C modification of the specific arginine tRNAs, which was not observed for other tRNAs (eg. tRNA-Ser-UGA) or controls. These findings were suggestive of c.1251C>A / pTyr417* being a partial LoF allele.

As the authors discuss, defects in tRNA modification have been associated with numerous human - among others neurological and neurodevelopmental - disorders (cited PMID: 30529455, table 1 of this review summarizing these incl. ADAT3-, PUS3-, TRMT1- related NDDs, etc).

Consider inclusion in the current panel with amber rating.

Sources: Literature
Intellectual disability - microarray and sequencing v3.1561 DALRD3 Konstantinos Varvagiannis gene: DALRD3 was added
gene: DALRD3 was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: DALRD3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DALRD3 were set to 32427860
Phenotypes for gene: DALRD3 were set to ?Developmental and epileptic encephalopathy 86, # 618910
Penetrance for gene: DALRD3 were set to Complete
Review for gene: DALRD3 was set to AMBER
Added comment: Biallelic pathogenic DALRD3 variants cause ?Developmental and epileptic encephalopathy 86 (# 618910).

Lentini et al (2020 - PMID: 32427860) report 2 sibs born to first cousin parents, homozygous for a DALRD3 pathogenic variant.

Both exhibited hypotonia, severe global DD and epilepsy (onset of seizures at the age 6-7m, poorly controlled by AEDs in one) corresponding overall to an developmental and epileptic encephalopathy. The authors reported subtle dysmorphic features. Other findings included GI concerns (in both) with microcephaly, CHD or renal anomalies in the younger.

WES guided by autozygome analysis revealed homozygosity for a DALRD3 stopgain variant (NM_001009996.3:c.1251C>A/pTyr417*) with Sanger sequencing confirming status of the children and carrier state of the parents.

DALRD3 encodes DALR anticodon-binding domain-containing protein 3. A DALR

It's DALR anticodon-binding domain is similar to those found in arginyl-tRNA synthetases RARS1/2.

As the authors demonstrate, and (better) summarized in OMIM, its product is a tRNA-binding protein that interacts with METTL2 to facilitate 3-methylcytosine (m3C) modification - by METTL2 - at position 32 of the anticodon loop in specific arginine tRNAs, namely tRNA-Arg-UCU and tRNA-Arg-CCU. In particular, DALRD3 seems to serve as discrimination factor required for recognition of these specific tRNAs.

In addition to DALRD3, a DALR anticodon-binding domain is also found in arginyl-tRNA synthetases (the cytoplasmic RARS1, and mitochondrial RARS2).

Given the variant type observed, predicting truncation of the protein and/or NMD, in LCLs from the 2 sibs (and comparison with controls) the authors demonstrated that the levels of full-length DALRD3 were decreased in cell lysates, with severe reduction (/loss) of m3C modification of the specific arginine tRNAs, which was not observed for other tRNAs (eg. tRNA-Ser-UGA) or controls. These findings were suggestive of c.1251C>A / pTyr417* being a partial LoF allele.

As the authors discuss, defects in tRNA modification have been associated with numerous human - among others neurological and neurodevelopmental - disorders (cited PMID: 30529455, table 1 of this review summarizing these incl. ADAT3-, PUS3-, TRMT1- related NDDs, etc).

Consider inclusion in the current panel with amber rating.
Sources: Literature
Intellectual disability - microarray and sequencing v3.812 TRMT10A Catherine Snow Source: Expert Review Amber was removed from gene: TRMT10A
Intellectual disability - microarray and sequencing v3.0 TRMT1 Louise Daugherty Tag watchlist was removed from gene: TRMT1.
Intellectual disability - microarray and sequencing v3.0 TRMT1 Louise Daugherty commented on gene: TRMT1
Intellectual disability - microarray and sequencing v2.826 TRMT1 Rebecca Foulger commented on gene: TRMT1: Removed 'watchlist' tag following promotion of gene rating from Amber to Green.
Intellectual disability - microarray and sequencing v2.826 TRMT1 Rebecca Foulger Phenotypes for gene: TRMT1 were changed from autosomal recessive intellectual disorder; ARID to autosomal recessive intellectual disorder; ARID; Mental retardation, autosomal recessive 68, 618302; Global developmental delay; Intellectual disability
Intellectual disability - microarray and sequencing v2.825 TRMT1 Rebecca Foulger Publications for gene: TRMT1 were set to 21937992; 26308914
Intellectual disability - microarray and sequencing v2.824 TRMT1 Rebecca Foulger Classified gene: TRMT1 as Green List (high evidence)
Intellectual disability - microarray and sequencing v2.824 TRMT1 Rebecca Foulger Added comment: Comment on list classification: Updated rating from Amber to Green based on the additional recent publication provided by Konstantinos Varvagiannis. PMID:30289604 (Blaesius et al., 2018) report 4 further patients from 2 unrelated consanguineous Pakistani families with homozygous variants in TRMT1 (a 32 bp deletion, and a G>T transversion predicted to result in abberrant splicing and LOF). All four patients had mild-to -moderate intellectual disability. This brings the total number of unrelated cases to four (the previous two cases coming from PMIDs:21937992 and PMID:26308914) . With functional studies in PMID:28784718 (Dewe et al., 2017), there is now sufficient evidence for a Green (diagnostic-grade) rating.
Intellectual disability - microarray and sequencing v2.824 TRMT1 Rebecca Foulger Gene: trmt1 has been classified as Green List (High Evidence).
Intellectual disability - microarray and sequencing v2.564 TRMT1 Konstantinos Varvagiannis reviewed gene: TRMT1: Rating: GREEN; Mode of pathogenicity: None; Publications: 30289604, 21937992, 26308914, 28784718; Phenotypes: Global developmental delay, Intellectual disability, Seizures, Microcephaly; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal; Current diagnostic: yes
Intellectual disability - microarray and sequencing v2.468 TRMT10A Louise Daugherty Source Victorian Clinical Genetics Services was added to TRMT10A.
Intellectual disability - microarray and sequencing TRMT1 Rebecca Foulger commented on TRMT1
Intellectual disability - microarray and sequencing TRMT1 Rebecca Foulger commented on TRMT1
Intellectual disability - microarray and sequencing TRMT10A BRIDGE consortium edited their review of TRMT10A
Intellectual disability - microarray and sequencing TRMT10A BRIDGE consortium edited their review of TRMT10A
Intellectual disability - microarray and sequencing TRMT10A Louise Daugherty classified TRMT10A as amber
Intellectual disability - microarray and sequencing TRMT10A Louise Daugherty commented on TRMT10A
Intellectual disability - microarray and sequencing TRMT10A BRIDGE consortium reviewed TRMT10A