Supplementary Material for: Expanding Insights into KCTD7-Related Drug-Resistant Epilepsy: Three Novel Mutations in a Cohort of Iranian Pediatric Patients

KCTD7-related epilepsy is a rare neurogenetic disorder characterized by marked genetic and phenotypic heterogeneity, typically presenting with early onset and often exhibiting poor response to conventional antiseizure medications. We performed exome sequencing in 134 Iranian pediatric patients with drug-resistant epilepsy and selected mutations in the KCTD7 gene. The pathogenicity of the identified variants was assessed using multiple in silico prediction tools and classified according to the ACMG guidelines. Additionally, we reviewed the genotype–phenotype correlations and treatment histories of all reported cases with KCTD7 mutations. Three novel homozygous variants—c.14C>T (p.Thr5Met), c.840delC (p.Ile281Serfs*11), and c.746T>G (p.Val249Gly)—were identified in four patients. Significant phenotypic heterogeneity was observed among patients, with disease severity ranging from mild to profound. Independent in silico analyses of each variant yielded concordant results, consistently predicting their potential to impact the structure and function of the KCTD7 protein. To date, 72 patients from 55 families have been reported, including 26.66% of homozygous cases born to non-consanguineous parents, and 37% of reported variants localized within BTB domain. Although 88.9% of patients experienced seizure onset before age two, clinical trajectories were highly variable. Among 45 patients with treatment data, valproate, levetiracetam, and clonazepam were the most frequently prescribed antiseizure medications; however, seizure control remained inconsistent. Notably, we observed subfertility in two heterozygous fathers, an unexpected finding that may suggest a potential role for KCTD7 beyond the central nervous system. These findings expand the mutational and phenotypic landscape of KCTD7-related epilepsy and underscore its clinical heterogeneity and therapeutic challenges.KCTD7相关癫痫是一种罕见的神经遗传性疾病，以显著的遗传与表型异质性为核心特征，通常起病早，且往往对常规抗癫痫药物反应不佳。本研究对134例伊朗耐药性癫痫儿科患者开展外显子测序，成功筛选出KCTD7基因的突变位点。研究采用多种计算机模拟预测工具评估所鉴定变异的致病性，并依据美国医学遗传学与基因组学学会（American College of Medical Genetics and Genomics, ACMG）指南对变异进行分类。此外，本研究还回顾了所有已报道的KCTD7突变病例的基因型-表型相关性与治疗史。本研究在4例患者中鉴定出3种新型纯合变异：c.14C>T (p.Thr5Met)、c.840delC (p.Ile281Serfs*11)以及c.746T>G (p.Val249Gly)。患者之间存在显著的表型异质性，疾病严重程度跨度从轻度至极重度。针对每个变异的独立计算机模拟分析结果一致，均预测这些变异可能对KCTD7蛋白的结构与功能产生影响。截至目前，全球已报道来自55个家庭的72例患者，其中26.66%为非近亲生育父母所生的纯合子病例，37%的已报道变异定位于BTB结构域（BTB domain）。尽管88.9%的患者在2岁前出现癫痫发作，但临床病程存在高度异质性。在45例具备完整治疗记录的患者中，丙戊酸钠、左乙拉西坦与氯硝西泮是最常开具的抗癫痫药物，但癫痫控制效果始终不稳定。值得注意的是，本研究在2名杂合子父亲中观察到生育力低下的情况，这一意外发现提示KCTD7可能在中枢神经系统之外发挥潜在作用。本研究结果拓展了KCTD7相关癫痫的突变与表型谱，同时凸显了该疾病的临床异质性与治疗挑战。