Department of Oral and Maxillofacial Surgery, Amsterdam UMC/Emma Children's Hospital, and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam, The Netherlands.
Laboratory of Genome Diagnostics, Amsterdam UMC, University of Amsterdam, Department of Clinical Genetics, Amsterdam Reproduction and Development, Amsterdam, The Netherlands.
Int J Oral Maxillofac Surg. 2020 Nov;49(11):1464-1469. doi: 10.1016/j.ijom.2020.02.002. Epub 2020 Apr 3.
Hemifacial hyperplasia (HFH) is characterized by an increase in volume of all affected tissues of half of the face. It is present at birth, subsequently grows proportionally, and stops growing before adulthood. Unilateral condylar hyperplasia (UCH) consists of progressive asymmetric growth of the mandible and develops typically in early adulthood. Both disorders have an unknown aetiology. The overgrowth limited to one body part suggests somatic mosaicism, as this has been found in other similar localized overgrowth disorders. Often this includes a variant in a gene in the (PIK3CA)/PI3K/(PTEN)/AKT1/mTOR pathway. Here we report the case of an HFH patient with asymmetry present at birth, in whom a progressive growth pattern similar to UCH subsequently occurred, causing marked mandibular asymmetry. A condylectomy was successfully performed to stop the progressive growth. Somatic mosaicism for a mutation in PIK3CA was detected in the condylar tissue. This finding might indicate that both HFH and UCH can be caused by variants in genes in the (PIK3CA)/PI3K/(PTEN)/AKT1/mTOR pathway, similar to other disorders that result in asymmetrical bodily overgrowth.
半侧颜面肥大症（HFH）的特征是面部单侧所有受影响组织的体积增加。它在出生时就存在，随后按比例生长，并在成年前停止生长。单侧髁突肥大症（UCH）由下颌骨的进行性不对称生长组成，通常在成年早期发展。这两种疾病的病因都未知。这种仅局限于身体某一部分的过度生长提示体细 胞嵌合体，因为在其他类似的局部过度生长疾病中也发现了这种情况。通常情况下，这包括（PIK3CA）/PI3K/（PTEN）/AKT1/mTOR 通路中的一个基因变异。在这里，我们报告了一例 HFH 患者，其出生时即存在不对称，随后出现类似 UCH 的进行性生长模式，导致明显的下颌骨不对称。通过髁突切除术成功地停止了进行性生长。在髁突组织中检测到 PIK3CA 基因突变的体细 胞嵌合体。这一发现可能表明，HFH 和 UCH 都可能是由（PIK3CA）/PI3K/（PTEN）/AKT1/mTOR 通路中的基因变异引起的，类似于导致身体不对称性过度生长的其他疾病。
