The CAMK2B gene encodes the β‐subunit of calcium/calmodulin‐dependent protein kinase II (CAMK2), an enzyme that has crucial roles in synaptic plasticity, especially in hippocampal and cerebellar neurons. Heterozygous variants in CAMK2B cause a rare neurodevelopmental disorder, with 40% of the reported cases sharing the same variant: c.416C>T, p.(P139L). This case report describes a 22‐year‐old patient with this recurrent variant, who presents with severe intellectual disability, absence of language, hypotonia, microcephaly, dysmorphic features, epilepsy, behavioral abnormalities, motor stereotypies, optic atrophy, and progressive cerebellar atrophy. Notably, this patient is the oldest reported so far and allows us to better delineate the clinical phenotype associated with this variant, adding clinical aspects never described before, such as epilepsy, optic atrophy, scoliosis, and neuroradiological changes characterized by progressive cerebellar atrophy.

中文翻译：

---

与CAMK2B基因复发性新变异p。（P139L）相关的严重智力障碍，语言障碍，癫痫，小头畸形和进行性小脑萎缩：病例报告和简要回顾。

所述CAMK2B基因编码钙的β亚单位/钙调蛋白依赖性蛋白激酶II（CAMK2），其具有在突触可塑性关键作用的酶，特别是在海马和小脑的神经元。CAMK2B中的杂合变体引起罕见的神经发育障碍，报告的病例中有40％具有相同的变体：c.416C> T，p。（P139L）。该病例报告描述了一名22岁的复发性变异患者，其表现为严重智力障碍，语言缺失，肌张力低下，小头畸形，畸形，癫痫病，行为异常，运动刻板印象，视神经萎缩和进行性小脑萎缩。值得注意的是，该患者是迄今为止报道最久的患者，它使我们能够更好地描述与该变异相关的临床表型，增加了以前从未描述过的临床方面，例如癫痫，视神经萎缩，脊柱侧弯和以进行性小脑萎缩为特征的神经放射学改变。