Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.
The NM_002839.4(PTPRD):c.5534+7_5534+8insAGTTACAGTTCAAGAAGGGTAAGTT variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type INS_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Uncertain significance (★).
PTPRD (HGNC:9668): (protein tyrosine phosphatase receptor type D) The protein encoded by this gene is a member of the protein tyrosine phosphatase (PTP) family. PTPs are known to be signaling molecules that regulate a variety of cellular processes including cell growth, differentiation, mitotic cycle, and oncogenic transformation. This PTP contains an extracellular region, a single transmembrane segment and two tandem intracytoplasmic catalytic domains, and thus represents a receptor-type PTP. The extracellular region of this protein is composed of three Ig-like and eight fibronectin type III-like domains. Studies of the similar genes in chicken and fly suggest the role of this PTP is in promoting neurite growth, and regulating neurons axon guidance. Multiple alternatively spliced transcript variants of this gene have been reported. A related pseudogene has been identified on chromosome 5. [provided by RefSeq, Jan 2010]
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing
The 5534+7_5534+8ins25 variant in PTPRD has not been previously identified in individuals with familial angiolipomatosis. Data from large population studies is insufficient to assess the frequency of this variant. This variant results in an insertion of 25 bases into intron 44 and computational tools suggest the creation of an alternative 5' splice site downstream of the normal exon-intron boundary. However, this variant does not cause a change at the conserved (+1/+2) positions in the splice site consensus sequence and splice prediction tools do not suggest an impact to the canonical (normal) splice site. Therefore, it is not possible to predict whether this insertion will result in abnormal splicing without functional analysis. In summary, without additional studies, the clinical significance of this variant cannot be determined with certainty. -