An adult with 3-M syndrome: BMJ case report
3-M syndrome is a rare autosomal recessive disorder characterised by short stature, dysmorphic facial features and skeletal abnormalities.

In this case, a 23-year-old male was diagnosed with 3-M syndrome in the oral medicine department during a routine dental visit. He had a triangular-shaped face with a prominent mouth, thick patulous lips, long philtrum, pointed chin, broad, fleshy nose with anteverted nostrils, and curvilinear eyebrows. He also exhibited mild midface hypoplasia with malar flattening and downward slanting eyes. He had prominent trapezius muscles, marked hyperlordosis and was 125 cm in height.

Lumbar spinal radiography showed relatively tall, narrow vertebral bodies. The lateral cephalometric radiograph of this patient showed the direction of growth was predominantly vertical (59%) and the lower gonial angle was increased (86°). The upper incisors were far ahead (+22 mm) of the NPog line. Sassouni analysis revealed that the maxilla was rotated downwards posteriorly and the mandible was rotated downwards anteriorly.

This abnormal rotation of the jaw resulted in a skeletal open bite. Phased orthodontic treatment and orthognathic surgery was recommended; the surgery plan includes bimaxillary Le Fort I osteotomy with anterior maxillary osteotomy and bilateral sagittal split osteotomy.

Learning points
• 3-M syndrome is a rare autosomal recessive disorder caused by mutations in the CUL7, OBSL1 and CCDC8 genes.

• The syndrome is characterised by low birth weight and proportionate dwarfism, while a skeletal survey reveals characteristic features including slender, long bones and ribs, particularly during childhood.

• If 3-M syndrome is suspected, evaluation and counselling by a medical genetics team is recommended to establish the diagnosis, guide care management, and provide reproductive counselling for the patient and their family.

Know more here:
1 share