Coffin-Siris syndrome is an autosomal dominant disorder with neurological, cardiovascular, and gastrointestinal symptoms. Patients with Coffin-Siris syndrome typically have variable degree of developmental delay or intellectual disability, muscular hypotonia, dysmorphic facial features, sparse scalp hair, but otherwise hirsutism and fifth digit nail or distal phalanx hypoplasia or aplasia. Coffin-Siris syndrome is caused by pathogenic variants in 12 different genes including SMARCB1 and ARID1A. Pathogenic SMARCB1 gene variants cause Coffin-Siris syndrome 3 whereas pathogenic ARID1A gene variants cause Coffin-Siris syndrome 2. Here, we present two prenatal Coffin-Siris syndrome cases with autosomal dominant pathogenic variants: SMARCB1 gene c.1066_1067del, p.(Leu356AspfsTer4) variant, and a novel ARID1A gene c.1920+3_1920+6del variant. The prenatal phenotype in Coffin-Siris syndrome has been rarely described. This article widens the phenotypic spectrum of prenatal Coffin-Siris syndrome with severely hypoplastic right ventricle with VSD and truncus arteriosus type III, persisting left superior and inferior caval vein, bilateral olfactory nerve aplasia, and hypoplastic thymus. A detailed clinical description of the patients with ultrasound, MRI, and post mortem pictures of the affected fetuses showing the wide phenotypic spectrum of the disease is presented.

中文翻译：

---

产前棺材-天狼星综合征：扩大该疾病的表型和基因型谱。

Coffin-Siris 综合征是一种常染色体显性遗传疾病，具有神经系统、心血管和胃肠道症状。Coffin-Siris 综合征患者通常有不同程度的发育迟缓或智力障碍、肌肉张力减退、面部特征畸形、头皮毛发稀疏，但还有多毛症和第五指指甲或远端指骨发育不全或发育不全。Coffin-Siris 综合征是由 12 个不同基因的致病变异引起的，包括 SMARCB1 和 ARID1A。致病性 SMARCB1 基因变异导致 Coffin-Siris 综合征 3，而致病性 ARID1A 基因变异导致 Coffin-Siris 综合征 2。在此，我们介绍两例具有常染色体显性致病变异的产前 Coffin-Siris 综合征病例：SMARCB1 基因 c.1066_1067del，p.(Leu356AspfsTer4)变体，以及一个新的 ARID1A 基因 c.1920+3_1920+6del 变体。Coffin-Siris 综合征的产前表型很少被描述。本文拓宽了产前 Coffin-Siris 综合征的表型谱，该综合征伴有严重右心室发育不全、室间隔缺损和动脉干 III 型、左上、下腔静脉持续存在、双侧嗅神经发育不全和胸腺发育不全。提供了患者的详细临床描述，包括超声、MRI 和受影响胎儿的尸检照片，显示了该疾病的广泛表型谱。