Hand hyperphalangism leading to shortened index fingers with ulnar deviation, hallux valgus, mild facial dysmorphism and respiratory compromise requiring assisted ventilation are the key features of Chitayat syndrome. This condition results from the recurrent heterozygous missense variant NM_006494.2:c.266A>G; p.(Tyr89Cys) in ERF on chromosome 19q13.2, encoding the ETS2 repressor factor (ERF) protein. The pathomechanism of Chitayat syndrome is unknown. To date, seven individuals with Chitayat syndrome and the recurrent pathogenic ERF variant have been reported in the literature. Here, we describe six additional individuals, among them only one presenting with a history of assisted ventilation, and the remaining presenting with variable pulmonary phenotypes, including one individual without any obvious pulmonary manifestations. Our findings widen the phenotype spectrum caused by the recurrent pathogenic variant in ERF, underline Chitayat syndrome as a cause of isolated skeletal malformations and therefore contribute to the improvement of diagnostic strategies in individuals with hand hyperphalangism.

中文翻译：

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Chitayat综合征的可变肺部表现：另外六个受影响的个体。

Chitayat综合征的主要特征是手的高指指法导致食指缩短，尺偏，拇指外翻，轻度面部畸形和需要辅助通气的呼吸困难。这种情况是由于复发性杂合错义变体NM_006494.2：c.266A> G导致的；19q13.2号染色体上ERF中的p。（Tyr89Cys），编码ETS2阻遏因子（ERF）蛋白。Chitayat综合征的发病机制尚不清楚。迄今为止，有7位患有Chitayat综合征和复发性致病性ERF的个体文献中已有报道。在这里，我们描述了另外六个人，其中只有一个具有辅助通气史，其余的具有可变的肺表型，包括一个没有明显肺部表现的人。我们的发现拓宽了由ERF反复致病性变异引起的表型谱，强调Chitayat综合征是孤立的骨骼畸形的原因，因此有助于改善手高手指症患者的诊断策略。