Synaptotagmin-1 (SYT1) plays a pivotal role in regulating presynaptic processes, including neurotransmitter release. SYT1 variants perturb synaptic vesicle endocytosis and exocytosis, resulting in a series of neurodevelopmental disorders defined as Baker-Gordon syndrome. Herein, we report the case of a newborn with dysmorphic facial appearance, severe hypotonia, poor feeding, gastroesophageal reflux, and an inability to eat and breathe, diagnosed with Baker–Gordon syndrome. A retrospective search was performed on a newborn with Baker-Gordon syndrome. Medical charts were reviewed, with focus on the clinical presentation, diagnostic process, and treatment outcomes. Whole-genome high-throughput DNA sequencing was performed to identify genetic variants. Whole-exome sequencing identified the likely pathogenic variant as SYT1 C.551 T > C(p.V184A). Sanger sequencing results indicated that this variant was a de novo mutation in a conservative site located in the C2A domain of the protein. The patient died at 57 days old because of severe feeding and breathing problems. Our findings of a novel lethal variant in the C2A domain of SYT1 in the youngest patient diagnosed infantile Baker-Gordon syndrome who presented with the most severe hypotonia reported to date expands the spectrum of SYT1- associated neurodevelopmental disorders.

Synaptotagmin-1 (SYT1) 在调节突触前过程（包括神经递质释放）中发挥着关键作用。 SYT1 变异扰乱突触小泡的胞吞作用和胞吐作用，导致一系列被定义为贝克-戈登综合征的神经发育障碍。在此，我们报告一例新生儿，其面部外观畸形、严重肌张力低下、喂养不良、胃食管反流、无法进食和呼吸，被诊断为贝克-戈登综合征。对一名患有贝克-戈登综合征的新生儿进行了回顾性调查。对医疗图表进行了审查，重点是临床表现、诊断过程和治疗结果。进行全基因组高通量 DNA 测序来鉴定遗传变异。全外显子组测序鉴定出可能的致病变异为 SYT1 C.551 T > C(p.V184A)。 Sanger测序结果表明，该变异是位于蛋白质C2A结构域保守位点的从头突变。该患者因严重的喂养和呼吸问题于 57 天时死亡。我们在诊断为婴儿贝克戈登综合征的最年轻患者中发现了 SYT1 C2A 结构域中的一种新的致死变异，该患者表现出迄今为止报道的最严重的肌张力低下，这扩大了 SYT1 相关神经发育障碍的范围。