Facial and dental characteristics of the patient. The face was long and narrow and showed signs of third nerve palsy, grimacing smile, pinched and hump nose, maxillary retrognathia compared to the mandible, and skeletal Class III malocclusion without microencephaly (A,B). Dental examination revealed V-shaped and high arched palate, crowding of the teeth, anterior open bite, many dental caries, teeth fractures and ectopic eruptions, and narrow maxillary width compared to the mandible (C–E).

Skeletal findings of the patient. The hands showed brachydactyly (A) and angulation of the 5th fingers (B). Broad halluces and hypertrichosis were observed in the toes (C,D).

Right vertebral artery angiography of the patient. Anterior–posterior view of the right vertebral artery (A,B). Compared with the normal perforator (yellow arrow), the perforators of both posterior cerebral arteries (black arrows) were tortuous and dilated. Short segmental dilatation and aneurysm formation of the right anterior inferior cerebellar artery (red arrow) was noted.

Comparison of visceral angiograms between the patient’s hepatic artery (A) and a normal hepatic artery (B). Overall, the “pruned branches” is a sign of normal peripheral hepatic arteries with extensive intrahepatic corkscrew and tortuous collateral arteries (A). Abrupt cut-off of second order branch of the hepatic artery types A6 and A7 (yellow arrows). Fine corkscrew collateral arteries along the A6 running course that replaces the normal A6 branch (white arrow heads). Intrahepatic tortuous collateral arteries developed in the peripheral liver (red arrows). Multiple stenosis and focal ectasia of the segmental hepatic artery (A8). This lead to the complete obstruction of the arteries and subsequent collateral development (green arrows). The normal A6 hepatic artery (B) showed typical smooth peripheral tapering out of the segmental hepatic artery (A6) with side-by-side ramification of the intrahepatic branches (yellow arrows).

Electropherograms of EP300 and PLAU obtained using Sanger sequencing. Two heterozygous missense variants in EP300 (A) and PLAU (B) were identified as de novo.

Knockdown of ep300a and plaub caused impaired intersegmental vessel (ISV) formation in zebrafish. Lateral views of the trunk of Tg(flk:gfp) zebrafish larvae (dorsal or ‘to the top’ and anterior or ‘to the left’) at 3 days post-fertilization (dpf) (A–H). Arrows indicate ISVs with abnormal branch formation. Arrowheads indicate ISVs with abnormal shape. Quantification of the number of embryos with ISV defects (I) in the control, ep300a, ep300b, plaua, and plaub morpholino (MO)-injected larvae at 3 dpf ([Control MO], normal: 97.43%, less: 2.57%, severe: 0% (n = 34); [ep300a MO], normal: 0% less: 40.27%, severe: 59.73%, (n = 37); [ep300b MO], normal: 43.25%, less: 56.75%, severe: 0%, (n = 37); [plaua MO], normal: 90.97%, less: 9.03%, severe: 0%, (n = 36); [plaub MO], normal: 11.43%, less: 8.57%, severe: 80%, (n = 35); [ep300a/plaub MO], normal: 0%, less: 5.41%, severe: 94.59%, (n = 37)). Quantification of defective ISVs (J) in the control, ep300a, ep300b, plaua, and plaub MO-injected larvae and ep300a MO + RNA and plaub MO + RNA-injected larvae at 3 dpf (Control MO: 0.72 ± 0.27 (n = 11), ep300a MO: 6.62 ± 0.49 (n = 13), ep300a MO + RNA: 1.9 ± 0.43 (n = 10), ep300b MO: 2.54 ± 0.27 (n = 13), plaua MO: 1.39 ± 0.24 (n = 13), plaub MO: 5.83 ± 0.65 (n = 12), plaub MO + RNA: 0.9 ± 0.18 (n = 10), ep300a/plaub MO: 9.15 ± 0.73 (n = 13). **p < 0.01, ***p < 0.01, ****p < 0.0001; scale bar = 100 µm).

Knockdown of ep300a and plaub caused the vascular occlusion phenotype in zebrafish. Lateral views of the trunk of Tg(gata1:dsred) zebrafish larvae (dorsal or ‘to the top’ and anterior or ‘to the left’) at 3 days post-fertilization (dpf) (A–D). Arrowheads indicate the slowly circulating red blood cells (RBCs) in the intersegmental vessels (ISVs). The bracketed area indicates stalled RBCs in the ISVs. Analysis of RBC circulation (E) in the control, ep300a, and plaub morpholino (MO)-injected larvae at 3 dpf (Control MO: 41.39 ± 2.39 (n = 23), ep300a MO: 31.97 ± 2.78 (n = 22), plaub MO: 18.79 ± 1.68 (n = 19), ep300a/plaub MO: 9.50 ± 2.01 (n = 16); *p < 0.05, ****p < 0.0001; scale bar = 100 µm).