The KCNH1 gene (OMIM #603,305) encodes a voltage-gated potassium channel primarily found in the central nervous system. Recent discoveries have linked pathogenic variations in this gene to Temple-Baraitser syndrome (TMBTS, OMIM #611,816) and Zimmermann-Laband syndrome (ZLS, OMIM #135,500). A common manifestation of these syndromes is gingival fibromatosis, which may partially or completely cover tooth crowns, leading in some cases to functional and aesthetic problems, as well as delayed tooth eruption. A four-year-old boy and his parents first consulted for delayed primary molars eruption. Shortly after birth, he was diagnosed with a developmental encephalopathy caused by a de novo pathogenic variant in KCNH1. The first step of oral treatment consisted of myofunctional and speech/language therapy to stimulate biting and chewing. It also helped with the rehabilitation of proper tongue function. This was followed by a gingivoplasty to expose the submerged teeth. We propose a clinical approach to optimize disease management. This aims to minimize complications associated with this rare disorder. This case illustrates the need for appropriate and early gingivoplasty to prevent teeth impaction and restore dental function. Additionally, it explores potential complications and provides grounds for a comprehensive protocol for managing gingival fibromatosis for patients with KCNH1 variant.

The NALCN encodes a sodium ion leak channel that regulates nerve-resting conductance and excitability. NALCN variants are associated with two neurodevelopmental disorders, one is CLIFAHDD (autosomal dominant congenital contractures of the limbs and face, hypotonia, and developmental delay, OMIM #616266) and another is IHPRF (infantile hypotonia with psychomotor retardation, and characteristic facies 1, OMIM #615419). In the current study, a Chinese infant that manifested abnormal facial features, adducted thumbs, and neurodevelopmental retardation was diagnosed with CLIFAHDD syndrome. A trio-based whole-exome sequencing revealed that the infant harbored a de novo variant of the NALCN gene (c.4300A>G, p.I1434V). Our findings further enriched the variant spectrum of the NALCN gene and may expand the clinical range of NALCN-related disorders.

Congenital thumb anomalies are common and have a major impact given the specific functional role of the thumb. They may occur alone or as part of a multiple congenital anomaly syndrome. The primary goal of surgical management is to improve or restore pincer grip. In patients with 'congenital' trigger thumb, the A1 pulley must be released if the interphalangeal joint remains in fixed flexion. Thumb duplication is generally managed by reconstruction of the thumb from the predominant (ulnar-based) digit; the accessory (radial-based) digit is excised after collection of its tissue components needed for the reconstruction programme. Thumb aplasia requires pollicisation of the index finger by island flap transfer of the second ray to give it the shape, position, and function of a thumb. Among patterns of digital hypoplasia, some require reconstruction of the existing thumb and others excision of the rudimentary thumb followed by pollicisation. In patients with aplasia of multiple hand digits, a toe transfer may be considered when there is no natural tendency to develop digital prehension at the hand.