What is Ohdo syndrome, SBBYS Variant (SBBYSS)?
Ohdo syndrome is a rare genetic condition that affects multiple parts of the body. Severe intellectual disability is a major syndrome.
To date, there are 19 recorded cases of the syndrome worldwide and it is thought to occur in more than 1 in 1 million live births worldwide.
Syndrome Synonyms:
Mental Retardation, Congenital Heart Disease, Blepharophimosis, Blepharoptosis, and Hypoplastic Teeth; Ohdo Blepharophimosis Syndrome; Say-Barber-Biesecker-Young-Simpson Syndrome; Young-Simpson Syndrome; YSS
What gene change causes Ohdo syndrome, SBBYS Variant (SBBYSS)?
Changes in the KAT6 gene are responsible for the syndrome. The majority of diagnosed cases so far have been de novo mutations.
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 which occurs during the reproductive process.
What are the main symptoms of Ohdo syndrome, SBBYS Variant (SBBYSS)?
A major symptom of the syndrome is severe intellectual disability, as well as limited to zero speech development.
Unique physical and facial characteristics of the syndrome include underdeveloped eyelids that cover part of the eye, a mask like, immobile face, a small mouth, small pointed teeth, thin upper lip, a large nasal tip, large toes and very long thumbs. A cleft palate occurs in 1/3 of all individuals with the syndrome.
Missing knee caps, or underdeveloped knee caps are also a major physical feature of the syndrome.
Other health conditions associated with the syndrome include heart defects, in 50% of individuals, feeding issues, low muscle gone and thyroid abnormalities.
Possible clinical traits/features:
Strabismus, Sparse and thin eyebrow, Ptosis, Tented upper lip vermilion, Respiratory failure, Ventricular septal defect, Arachnodactyly, Abnormality of the foot, Cleft palate, Camptodactyly of toe, Wide nasal bridge, Advanced eruption of teeth, Atrial septal defect, Blepharophimosis, Nystagmus, Open mouth, Sensorineural hearing impairment, Widely spaced teeth, Seizure, Proteinuria, Stenosis of the external auditory canal, Thin vermilion border, Scrotal hypoplasia, Autosomal dominant inheritance, Pes planus, Patellar aplasia, Cryptorchidism, Conductive hearing impairment, Epicanthus, Everted lower lip vermilion, Clinodactyly of the 5th finger, Smooth philtrum, Feeding difficulties in infancy, External ear malformation, Atresia of the external auditory canal, Delayed eruption of teeth, Hypermetropia, Full cheeks, Depressed nasal bridge, Cognitive impairment, Visual impairment, Hypothyroidism, Hearing impairment, Short stature, Intellectual disability, Abnormality of dental enamel, Joint laxity, Joint hypermobility.
How is it diagnosed?
To find out if someone has a diagnosis of Ohdo syndrome, SBBYS Variant (SBBYSS), 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.
