Opitz-Kaveggia syndrome

What is Opitz-Kaveggia syndrome?

Also known as FG syndrome it is a rare genetic condition that presents mainly in males. Its symptoms affect multiple parts of the body. The syndrome mainly affects intelligence and behavior. The syndrome has been reported in several hundred families worldwide but it is generally believed to be largely underdiagnosed as a syndrome, mainly because it shares common symptoms with other conditions and disorders. The syndrome is more common in males, due to the way in which it is inherited.

This syndrome is also known as:
FG syndrome; FGS; Mental Retardation, Large Head, Imperforate Anus, Congenital Hypotonia, and Partial Agenesis of Corpus Callosum

What gene changes cause Opitz-Kaveggia syndrome?

Changes in the MED12 gene seem to be the most common cause of the syndrome. Lujan-Fryns and Ohdo syndrome are also both linked to mutations in this same gene.

The syndrome is inherited in an X-linked recessive pattern. Syndromes inherited in an X-linked recessive pattern generally only affect males. Males only have one X chromosome, and so one copy of a gene mutation on it causes the syndrome. Females, with two X chromosomes, only one of which will be mutated, are not likely to be affected.

What are the main symptoms of Opitz-Kaveggia syndrome?

The main symptoms of the syndrome include intellectual disability (mild to severe) and similar behaviors including hyperactivity and a short attention span. Affected individuals usually have delayed speech and language skills as well.

  • The unique facial features of the syndrome include widely spaced eyes and a large head.
  • Common physical features of the syndrome include low muscle tone, broad thumbs, and a wide first toe.
  • Constipation is a common symptom, as is obstruction in the anal opening.
  • Some individuals also have seizures, heart defects, and hernias.

Possible clinical traits/features:
Hypertelorism, High palate, Hiatus hernia, Depressed nasal bridge, Aplasia/Hypoplasia of the cerebellar vermis, Global developmental delay, Hypospadias, Autosomal dominant inheritance, Posteriorly rotated ears, Short lingual frenulum, Widow’s peak, Patent ductus arteriosus, Frontal bossing, Telecanthus, Prominent forehead, Thin upper lip vermilion, Strabismus, Pulmonary hypoplasia, Pulmonary arterial hypertension, Absent gallbladder, Ventricular septal defect, Umbilical hernia, Weak cry, Tracheoesophageal fistula, Muscular hypotonia, Inguinal hernia, Laryngeal cleft, Micrognathia, Intellectual disability, Diastasis recti, Ventriculomegaly, Smooth philtrum, Downslanted palpebral fissures, Agenesis of corpus callosum, Dysphagia, Conductive hearing impairment, Craniosynostosis, Cranial asymmetry, Cryptorchidism, Epicanthus, Coarctation of aorta, Cleft upper lip, Cleft palate, Anal stenosis, Anal atresia, Abnormality of the ureter, Abnormality of the kidney, Cavum septum pellucidum, Wide nasal bridge.

How is it diagnosed?

To find out if someone has a diagnosis of Opitz-Kaveggia syndrome, 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.

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