Abstract：
Abnormal hyperpolarization of the KCNK4 gene, expressed in the nervous system, brain, and periodontal ligament fibroblasts, leads to impaired neurotransmitter sensitivity, cardiac arrhythmias, and endocrine dysfunction, as well as, progressive cell proliferation. De novo gain of function variants in the KCNK4 gene were reported to cause a recognizable syndrome characterized by facial dysmorphism, hypertrichosis, epilepsy, intellectual/developmental delay, and gingival overgrowth (FHEIG, OMIM# 618381). FHEIG is extremely rare with only three reported cases in the literature. Herein, we describe the first inherited KCNK4 variant (c.730G>C, p.Ala244Pro) in an Egyptian boy and his mother. Variable phenotypic expressivity was noted as the patient presented with the full-blown picture of the syndrome while the mother presented only with hypertrichosis and gingival overgrowth without any neurological manifestations. The c.730G>C (p.Ala244Pro) variant was described before in a single patient and when comparing the phenotype with our patient, a phenotype-genotype correlation seems likely. Atrial fibrillation and joint laxity are new associated findings noted in our patient extending the clinical phenotype of the syndrome. Dental management was offered to the affected boy and a dramatic improvement was noted as the patient regained his smile, restored the mastication function, and resumed his psychological stability.
摘要：
KCNK4基因的异常超极化，在神经系统中表达，大脑,和牙周膜成纤维细胞，导致神经递质敏感性受损，心律失常,和内分泌功能障碍，还有,进行性细胞增殖。据报道，KCNK4基因的功能变异从头获得可引起以面部畸形为特征的可识别综合征，多毛症,癫痫,智力/发育迟缓，和牙龈过度生长(FHEIG，OMIM#618381)。FHEIG极为罕见，文献中仅报道了三例。在这里，我们描述了第一个继承的KCNK4变体(c.730G>C，p.Ala244Pro）在一个埃及男孩和他的母亲中。由于患者表现出综合征的全面图像，而母亲仅表现为多毛症和牙龈过度生长，而没有任何神经系统表现，因此注意到了表型表达。c.730G>C（p。Ala244Pro）变体之前在单个患者中进行了描述，并且在将表型与我们的患者进行比较时，表型-基因型相关性似乎很可能.心房颤动和关节松弛是我们患者发现的新的相关发现，扩展了该综合征的临床表型。为受影响的男孩提供了牙科管理，并且随着患者恢复微笑，出现了显着改善，恢复咀嚼功能，恢复了他的心理稳定.
