What is Multiple Synostoses syndrome?
Multiple Synostoses syndrome is a rare genetic syndrome, also sometimes known as WL syndrome. The syndrome affects mainly the development of the bones. Symptoms usually become apparent during childhood.
This syndrome is also known as:
Deafness-symphalangism Syndrome of Herrmann; Facio-audio-symphalagism syndrome; Facio-audio-symphalangism syndrome; Facioaudiosymphalangism Syndrome; Herrmann symphalangism; Multiple synostosis syndrome; Symphalangism-brachydactyly Syndrome; Synostoses, Multiple, with Brachydactyly; WL syndrome
What gene changes cause Multiple Synostoses syndrome (SYNS)?
Mutations in the NOG, GDF5, FGF9, and GDF6 genes are responsible for causing the different four types of this syndrome. All types are inherited in an autosomal dominant pattern.
In the case of autosomal dominant inheritance, just one parent is the carrier of the gene mutation, and they have a 50% chance of passing it onto each of their children. Syndromes inherited in an autosomal dominant inheritance are caused by just one copy of the gene mutation.
What are the main symptoms of Multiple Synostoses syndrome (SYNS)?
- One of the main symptoms of the syndrome is a condition known as proximal or Cushing’s symphalangism of the fingers. This is a condition where the proximal joints of the hands and feet are fused. This in turn leads to straight fingers that can not be bent.
- In some individuals, this symphalangism or fusing may also affect the hips and vertebrae (spinal column).
- Unique facial features of the syndrome include a long face, a broad nose, a short philtrum, a thin upper lip, and crossed eyes.
- Hearing loss is also associated with the syndrome.
Possible clinical traits/features:
Short sternum, Single transverse palmar crease, Autosomal dominant inheritance, Stapes ankylosis, Abnormal vertebral morphology, Aplastic/hypoplastic toenail, Anonychia, Aplasia/Hypoplasia of the middle phalanges of the hand, Absent distal interphalangeal creases, Absent distal phalanges, Brachydactyly, Dislocated radial head, Enlargement of the costochondral junction, Cutaneous finger syndactyly, Cubitus valgus, Spinal canal stenosis, Radial deviation of finger, Carpal synostosis, Tarsal synostosis, Progressive conductive hearing impairment, Proximal symphalangism of hands, Short lower limbs, Short philtrum, Thick upper lip vermilion, Thin upper lip vermilion, Strabismus, Clinodactyly, Waddling gait, Narrow face, Pectus excavatum, 2-3 toe syndactyly, Fusion of midphalangeal joints, Short humerus, Lower limb undergrowth, Hypoplastic nasal septum, Short foot, Underdeveloped nasal alae, Hypoplastic spinal processes, Short hallux.
How is it diagnosed?
To find out if someone has a diagnosis of Multiple Synosotoses syndrome (SYNS), it is important to have a consultation and evaluation with a clinical genetic specialist. Specialists may also suggest specific genetic testing or other types of tests to help reach a diagnosis. FDNA’s AI technology can help speed up the diagnostic process by analyzing facial features and other health information.
