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Intellectual disability syndromic and non-syndromic v0.3382 MORC2 Zornitza Stark Phenotypes for gene: MORC2 were changed from Charcot-Marie-Tooth disease, axonal, type 2Z, MIM #616688; Intellectual disability to Developmental delay, impaired growth, dysmorphic facies, and axonal neuropathy, MIM# 619090; Intellectual disability
Intellectual disability syndromic and non-syndromic v0.3381 MORC2 Zornitza Stark edited their review of gene: MORC2: Changed phenotypes: Developmental delay, impaired growth, dysmorphic facies, and axonal neuropathy, MIM# 619090, Intellectual disability
Intellectual disability syndromic and non-syndromic v0.2786 MORC2 Zornitza Stark reviewed gene: MORC2: Rating: GREEN; Mode of pathogenicity: None; Publications: 32693025; Phenotypes: Intellectual disability; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2786 MORC2 Zornitza Stark Marked gene: MORC2 as ready
Intellectual disability syndromic and non-syndromic v0.2786 MORC2 Zornitza Stark Gene: morc2 has been classified as Green List (High Evidence).
Intellectual disability syndromic and non-syndromic v0.2786 MORC2 Zornitza Stark Phenotypes for gene: MORC2 were changed from Charcot-Marie-Tooth disease, axonal, type 2Z, MIM #616688 to Charcot-Marie-Tooth disease, axonal, type 2Z, MIM #616688; Intellectual disability
Intellectual disability syndromic and non-syndromic v0.2785 MORC2 Zornitza Stark Publications for gene: MORC2 were set to https://doi.org/10.1016/j.ajhg.2020.06.013
Intellectual disability syndromic and non-syndromic v0.2784 MORC2 Zornitza Stark Classified gene: MORC2 as Green List (high evidence)
Intellectual disability syndromic and non-syndromic v0.2784 MORC2 Zornitza Stark Gene: morc2 has been classified as Green List (High Evidence).
Intellectual disability syndromic and non-syndromic v0.2783 MORC2 Konstantinos Varvagiannis gene: MORC2 was added
gene: MORC2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MORC2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: MORC2 were set to https://doi.org/10.1016/j.ajhg.2020.06.013
Phenotypes for gene: MORC2 were set to Charcot-Marie-Tooth disease, axonal, type 2Z, MIM #616688
Penetrance for gene: MORC2 were set to unknown
Mode of pathogenicity for gene: MORC2 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: MORC2 was set to GREEN
Added comment: The current review is based on a recent report by Sacoto et al (2020 - https://doi.org/10.1016/j.ajhg.2020.06.013).

While several previous studies focused on the phenotype of axonal motor and senory neuropathy in individuals with heterozygous MORC2 pathogenic variants (Charcot-Marie-Tooth disease, axonal, type 2Z, MIM #616688) some of them presented among others with hypotonia, muscle weakness, intellectual disability, microcephaly or hearing loss [refs provided by Sacoto et al - learning disabilities (in some patients) also listed in OMIM's clinical synopsis].

Sacoto et al present a cohort of 20 individuals having genetic testing for developmental delay or growth failure (with a single one for a diagnosis of sensorimotor neuropathy).

Overlapping features included DD, ID (18/20 - mild to severe), short stature (18/20), microcephaly (15/20) and variable craniofacial dysmorphisms. The authors comment that features suggestive of neuropathy (weakness, hyporeflexia, abnormal EMG/NCS) were frequent but not the predominant complaint. EMG/NCS abnormalities were abnormal in 6 out of 10 subjects investigated in this cohort. Other findings included brain MRI abnormalities (12/18 - in 5/18 Leigh-like lesions), hearing loss (11/19) and pigmentary retinopathy in few (5).

Affected subjects were found to harbor in all cases missense variants in the ATPase module of MORC2 [residues 1 to 494 - NM_001303256.1 - the module consists of an ATPase domain (aa 1-265), a transducer S5-like domain (266-494) and a coiled-coiled domain (CC1 - aa 282-361)].

Variants had occured mostly as de novo events although inheritance from a similarly affected parent was also reported.

Some of them were recurring within this cohort and/or the literature eg. c.79G>A/p.Glu27Lys (x5), c.260C>T/p.Ser87Leu (x2), c.394C>T/p.Arg132Cys (4x), c.1164C>G/p.Ser388Arg (x2), c.1181A>G/p.Tyr394Cys (x3).

MORC2 encodes an ATPase involved in chromatin remodeling, DNA repair and transcriptional regulation. Chromatin remodeling and epigenetic silencing by MORC2 is mediated by the HUSH (Human Silencing Hub) complex. Functional studies (MORC2-knockout HeLa cells harboring a HUSH-sensitive GFP reporter were transduced with wt or mt MORC2 followed by measurement of reporter repression) supported the deleterious effect of most variants known at the time (hyperactivation of HUSH-mediating silencing, in line with previous observations).

Overall this gene can be considered for inclusion in the ID panel with green rating. Also other gene panels (e.g. for short stature, microcephaly, hearing loss, pigmentary retinopathy, etc) if it meets the respective criteria for inclusion.
Sources: Literature