Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1PM2PM5PP3_Strong
The NM_000368.5(TSC1):āc.278T>Gā(p.Leu93Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as not provided (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L93V) has been classified as Uncertain significance.
TSC1 (HGNC:12362): (TSC complex subunit 1) This gene is a tumor suppressor gene that encodes the growth inhibitory protein hamartin. The encoded protein interacts with and stabilizes the GTPase activating protein tuberin. This hamartin-tuberin complex negatively regulates mammalian target of rapamycin complex 1 (mTORC1) signaling which is a major regulator of anabolic cell growth. This protein also functions as a co-chaperone for Hsp90 that inhibits its ATPase activity. This protein functions as a facilitator of Hsp90-mediated folding of kinase and non-kinase clients, including TSC2 and thereby preventing their ubiquitination and proteasomal degradation. Mutations in this gene have been associated with tuberous sclerosis and lymphangioleiomyomatosis. [provided by RefSeq, May 2022]
TSC1 Gene-Disease associations (from GenCC):
tuberous sclerosis
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
tuberous sclerosis 1
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, PanelApp Australia, Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
lung lymphangioleiomyomatosis
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
tuberous sclerosis complex
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Our verdict: Pathogenic. The variant received 10 ACMG points.
PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 14 uncertain in NM_000368.5
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr9-132925672-A-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 974549.Status of the report is criteria_provided_single_submitter, 1 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.982
Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);Gain of methylation at L93 (P = 0.0036);