Patient characteristics. (A) Flowchart depicting all patients with ATM in the UCSF registry and the 3 groups included in the statistical analyses (group 1: prenatal diagnosis, alive (n = 14); group 2: prenatal diagnosis, deceased (n = 5), and group 3, postnatal diagnosis, alive (n = 11). Group 1 included one patient with a nondeletion variant (SEA/Hb H Adana), and group 3 included 3 patients with alpha thalassemia nondeletion variants (homozygous Zurich-Albisrieden [n = 1], SEA/Hb H Adana [n = 2]). ∗Previously published patients: 4 patients in group 1^8,22,and 6 patients in group 3.^11,23 (B) Genotypes of patients prenatally or postnatally diagnosed. The prenatally diagnosed group included 49 patients with the following genotypes: homozygous SEA (n = 29), SEA/FIL (n = 16), SEA/THAI (n = 1), homozygous MED I (n = 1), homozygous BRIT (n = 1), and SEA/Hb Adana (n = 1). The postnatally diagnosed group included 11 patients with the following genotypes: SEA/SEA (n = 8), SEA/Hb Adana (n = 2), and homozygous Zurich-Albisrieden (n = 1). The black outline in the prenatal diagnosis group indicates genotypes that have deletions spanning the zeta-globin gene (THAI, FIL), which were not observed in the postnatal diagnosis group (P = .02, Fisher’s exact test). (C) Cardiothoracic ratio observed by ultrasonography at the indicated GAs. Each data point is a unique fetus, the lines indicate the fifth, fiftieth, and ninety-fifth percentiles.¹⁴ The triangle represents a patient with a nondeletion variant.