Reasoning
The governing ClinGen HBOP ATM PM3/BP2 specification requires affected A-T proband observations with the variant homozygous, in trans with a pathogenic/likely pathogenic ATM variant, phase unknown, or with an unidentified/VUS second variant, and assigns points from the documented phenotype and phase. The case evidence contains no affected-proband observation, second ATM allele, phase result, or qualifying homozygous A-T case for NM_000051.4:c.2377-18T>C (NP_000042.3:p.?). The variant was searched in ATM_PM3_BP2_1.5.pdf under c.2377-18T>C and p.?; no variant-specific entry was found, so no PM3 points or strength can be assigned.
Rule
ATM VCEP PM3: assign points per unrelated A-T proband according to phenotype and phase/zygosity; PM3 Supporting=1.0, Moderate=2.0, Strong=4.0, Very Strong=8.0 points.
Evidence considered
- ATM_PM3_BP2_1.5.pdf specifies PM3 for recessive A-T using affected-proband observations and phase/zygosity-specific points: confident phenotype is worth 4.0 points confirmed in trans, 2.0 phase unknown, 1.0 with an unidentified/VUS second variant, or 2.0 for homozygous observations; consistent phenotype receives half those values.
- The consolidated case evidence identifies the variant as NM_000051.4:c.2377-18T>C with protein annotation NP_000042.3:p.? but provides no affected-proband, second-allele, phase, or homozygous A-T observation applicable to PM3.
- The notation c.2377-18T>C and p.? was searched in ATM_PM3_BP2_1.5.pdf; no variant-specific table entry was found.
Still missing
- No entry for NM_000051.4:c.2377-18T>C, c.2377-18T>C, or p.? was found in ATM_PM3_BP2_1.5.pdf.
- Affected-proband observations and A-T phenotype classification are unavailable.
- A qualifying pathogenic/likely pathogenic ATM allele in trans, phase information, or qualifying homozygous A-T observations are unavailable.
Sources
vcep_atm_pm3_bp2_1_5