Table 4.

Diagnostic criteria for Legius syndrome according to Legius et al. (2021)

(A) The diagnostic criteria for Legius syndrome are met in an individual who does not have a parent diagnosed with Legius syndrome if both of the following criteria are present:

≥ 6 Café-au-lait macules bilaterally distributed and no other NF1-related diagnostic criteria except for axillary or inguinal frecklinga

A heterozygous pathogenic variant in SPRED1 with a variant allele fraction of 50% in an apparently normal tissue such as white blood cells

(B) A child of a parent who meets the diagnostic criteria specified in (A) merits a diagnosis of Legius syndrome if one or more of the criteria in (A) are present

^aThe presence of fewer than 6 café-au-lait macules does not exclude Legius syndrome