Proteus syndrome caused by novel somatic AKT1 duplication

Abstract

Proteus syndrome (PS) is a rare overgrowth disorder that presents with asymmetrical growth of the bone and fat tissues following a mosaic pattern mutation. The estimated worldwide incidence is approximately one in one million live births. Proteus syndrome causes disfigurement and psychological impact through its effects on somatic tissue. Due to its rarity and diversity of tissues involved, it represents a significant challenge to caregivers and multidisciplinary medical teams. Here, we report a Saudi girl, with a large left cervical mass discovered antenatally. This mass was identified as a growing cystic hygroma, and she had features of overgrowth and hemangiomas. Whole exome sequencing was negative from the blood lymphocytes and affected tissue sample. However, deletion duplication analysis from tissue shows a novel mosaic somatic mutation of the AKT1 gene. Somatic mutation remains an obstacle, and the geneticist has an essential role in its management, providing an established genetic diagnosis, prognosis, and family counselling.

Figure 1

Left cheek showing large cystic hygroma.

Figure 2

Left leg showing large epidermal nevi.

Figure 3

Left leg showing macro-syndactyly.

Figure 4

X ray of the feet showing the macrodactyly.

Figure 5

Magnetic resonance imaging of the head and neck showing the large multilocular cystic hygroma.