What is Marshall-Smith Syndrome?
Marshall-Smith syndrome is a rare disease that affects multiple parts of the body.
The main symptoms of the syndrome are advanced bone age, a failure to thrive (difficulty in gaining weight), characteristic facial features, and intellectual disability.
Causes of Marshall-Smith Syndrome
Gene changes in the NFIX gene are responsible for the syndrome.
For now, most cases of the syndrome are the result of a de novo or new mutation, making each case the first in a family.
In some cases, a genetic syndrome may be the result of a de-novo mutation and the first case in a family. In this case, this is a new gene mutation that occurs during the reproductive process.
Symptoms of Marshall-Smith Syndrome
The main symptoms of the syndrome are intellectual disability and developmental delay. This is usually accompanied by very severe breathing issues.
The unique facial features associated with the syndrome include a prominent forehead, widely spaced eyes that may also protrude, a depressed nasal bridge, a small nose, and a small jaw. A blue tint to the white of the eyes may also be present in affected individuals. Excessive hair growth has also been identified as a symptom of the syndrome.
Advanced bone age is another feature of the disease, along with a failure to thrive and to gain weight. Scoliosis, a curving of the spine, is also common.
Other medical issues related to the syndrome include heart defects (particularly septal defects), an umbilical hernia, and hearing loss.
Possible clinical traits/features:
Patent ductus arteriosus, Retrognathia, Autosomal dominant inheritance, Overfolded helix, Optic atrophy, Obstructive sleep apnea, Omphalocele, Open mouth, Thin skin, Shallow orbits, Short sternum, Atrial septal defect, Atlantoaxial dislocation, Aplasia/Hypoplasia of the cerebellum, Abnormality of the tongue, Accelerated skeletal maturation, Cerebral atrophy, Choanal stenosis, Choanal atresia, Blue sclerae, Macrogyria, Bullet-shaped middle phalanges of the hand, Bruising susceptibility, Joint hypermobility, Large sternal ossification centers, Laryngomalacia, Tall stature, Anteverted nares, Short nose, Micrognathia, Pectus excavatum, Intellectual disability, Muscular hypotonia, Low-set ears, Short distal phalanx of finger, Hypertelorism, Hypertrichosis, Cognitive impairment, Glossoptosis, Hearing impairment, Gingival overgrowth, Depressed nasal bridge, Hyperextensible skin, Hypoplasia of the odontoid process, Failure to thrive, Ventriculomegaly, Bowing of the long bones, Distal widening of metacarpals
Diagnosis and Testing
The initial testing for Marshall-Smith syndrome can begin with facial analysis screening with FDNA’s AI technology, which can identify the key markers of the syndrome and outline the need for further testing.
Based on clinical consultation with a genetic professional, different options for genetic testing will be proposed.
