b'Figure 12. St Georges Classification Algorithm of Primary Lymphatic Anomaliesdiagnosis can be used to inform the patient and familyMilroy disease is likely, and the patient should be members of inheritance patterns, likely prognosis, andtested for mutations in VEGFR3. If Milroy disease screening of diseases the patient or relatives may be atcan be confirmed, advice pertaining to natural risk of developing. The St. Georges classification hashistory, prognosis, and risks should be given to the been updated in 2020 and aligns with the 2018 ISSVApatient and their family.classification of vascular anomalies.6. If your patient has late-onset lymphedema, threeAs an example, for using the algorithm, follow thediagnoses remain on the differential. steps detailed below (and see Figure 12). a. L ymphedema distichiasis syndrome (LDS) due1. Start in the dark gray box titled Primary Lymphaticto mutations in the FOXC2 gene with associated varicose veins, congenital heart disease, cleft Anomaly and move through the pathway bypalate, spinal cysts, and renal problemsidentifying which subgroup to which your patient b. Emberger syndrome due to mutations in the belongs.2. Determine if your patient is syndromic (blue box),GATA2 gene with associated warts, monocyto-penia/pancytopenia, and predisposition to meaning that the patient exhibits a constellation ofmyelodysplasia and acute myeloid leukemiacharacteristics likely, including dysmorphic features.c. Meige disease for which no causal gene has3. If your patient does not have a genetic syndrome, been identified.determine if there are associated internal/systemic lymphatic problems (pink section). With new genes associated with the development4. If syndromes or systemic involvement have beenof lymphedema continuously being studied, theexcluded, move to the green section for congenitalalgorithm is likely to be revised as new developments swelling or the purple section for swelling thatoccur in the field of lymphedema research. comes on after the first year of life. Nonetheless, the latest version of the algorithm 5. If your patient has pedal lymphedema present atremains a good working model for the present genetic screening and counseling needs of patients and birth with no syndromic or systemic features, families affected by lymphedema 47 .| Standardized Approach for the Diagnosis and Management of Lymphedema (LE) and Lymphatic Diseases (LD)|37'