Ehlers-Danlos Syndrome (EDS), particularly the vascular subtype, can closely mimic ATS, presenting with translucent skin, easy bruising, and fragility of arteries, intestines, or uterus, and is associated with COL3A1 mutations. Cutis Laxa Syndromes feature loose, inelastic skin and may also include vascular anomalies such as arterial tortuosity, with differentiation reliant on clinical and genetic evaluation. Here, COL3A1 is linked to Andersen-Tawil syndrome.