Ninety-eight individuals were tested for VHL mutations--23 symptomatic and 75 asymptomatic individuals belonging to 16 families. Seven of the families had definite clinical criteria of VHL disease, five had sporadic hemangioblastoma, and four had CNS hemangioblastoma combined with minor visceral signs. Molecular genetic testing identified five germline mutations in six of the definite VHL families (sensitivity 85%), but none in the possible VHL and sporadic hemangioblastoma cases; four of these mutations had been previously described and one is a novel mutation present in two unrelated families. After patients carrying the mutation were identified, they underwent clinical screening and asymptomatic VHL-related lesions were identified in 43%.
PatientID: 23
KindredID: C
Case: Sex Unknown, 9Y0M, Mexican (Latino/Admixed American)
DiseaseAssertion: asymptomatic
FamilyInfo: At least 13 members in this family presented with the mutation. 5 were asymptomatic (ages 9, 12, 13, 17, and 29Y). Other family manifestations include: cerebellar, spinal, retinal HBs, pancreatic, hepatic, suprarenal and kidney cysts, epididymal cystadenoma, and RCC. Fig 1 displays family pedigree.
CasePresentingHPOs: N/A
CaseHPOFreeText: Patient was asymptomatic at the time, likely due to young age
CaseNotHPOs: N/A
CaseNotHPOFreeText: N/A
CasePreviousTesting: N/A
PreviouslyPublished: 20064270 (Here, the family cohort is given with a reportedly different variant of: p.G34Rfs*98 (c.99_100insA). Unclear of why this is or which most correctly corresponds to the family).
SupplementalData: N/A
Variant: p.T100Nfs*32 (c.298dupA)
LegacyVariant: c.1012_1013insA
CaseProblemVariantFreeText: The ‘1012_1013insA’ mutation is out-of-frame, leading to a modification of 31 amino acids downstream and a premature stop codon at nucleotides 5441-5443 (amino acid residue 131).
ClinVarID: N/A
CAID: CA2573129737 https://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/allele?hgvsOrDescriptor=NM_000551.3%3Ac.298dupA
gnomAD: N/A
VariantEvidence: The modified amino acids are located in a domain common to all pVHL isoforms, the highly conserved cctbinding domain of the protein, involved in the formation of the pVHL elongin complex that is crucial for tumor suppression. Furthermore, the mutant protein is prematurely truncated and lacks the C-terminal half of exon 2 and exon 3 completely, which includes the nuclear export signal and the elongin C binding site of pVHL. Thus, this truncated protein would affect the two functional isoforms of pVHL: the major isoform pVHL30 and pVHL19, but not isoform 2, which lacks exon 2 but is not functional
MutationType: plus_1_frameshift_variant; duplication
CivicName: T100Nfs*32 (c.298dupA)
MultipleGeneVariants: N/A