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The Disease — BBSOAS

Understanding Bosch-Boonstra-Schaaf Optic Atrophy Syndrome, linked to the NR2F1 gene.

Bosch-Boonstra-Schaaf Optic Atrophy Syndrome (BBSOAS) is a rare neurological disorder caused by a disruption of the NR2F1 gene, located on chromosome 5. It is an ultra-rare genetic disease.

BBSOAS is characterised by a wide range of clinical signs. The most common are visual impairment caused by optic atrophy, developmental delay and intellectual disability.

There are currently more than 500 known cases of BBSOAS worldwide. But because the syndrome was only described recently (in 2014), the actual number of patients is very likely underestimated.

Illustration de la recherche médicale sur le syndrome BBSOAS
+500known cases worldwide
2014first description of the syndrome
NR2F1gene involved (chromosome 5)
Clinical features

The clinical symptoms

Symptoms vary depending on the location of the mutation, deletion or mosaicism on the NR2F1 gene. Each patient is different.

  • Global developmental delay
  • Neuro-visual disorders: nystagmus, lower visual field loss, coloboma, amblyopia, epicanthus, strabismus, colour blindness, hyperopia, juvenile glaucoma, tunnel vision, low visual acuity that may require a white cane
  • Atrophy and/or hypoplasia of the optic nerve and/or cortical blindness
  • Severe language disorders, particularly on the expressive side
  • Dyspraxia (oro-facial, visuo-constructive spatial…)
  • Dysgraphia, dyscalculia, dyslexia…
  • Feeding difficulties, including oro-motor dysfunction
  • Sensory disorders: poor perception of pain from falls, of hot and cold, of salty and sweet, rare tears
  • Attention deficit disorder
  • Hyperkinesia
  • Sleep disorders
  • Abnormal hearing
  • Hypotonia
  • Epilepsy: myoclonus…
  • Mild to moderate intellectual disability (often excellent memory)
  • Autism spectrum disorders: restricted interests, repetitive behaviours, reduced social skills
  • Joint hypermobility
  • Bone malformations (bilateral coxa valga of the hips, flat feet, overly short Achilles tendons…)
  • Allergies and intolerances (heavy metals, gluten and casein…)
  • Childhood asthma
  • Urinary and faecal incontinence
  • Chiari malformation

This page is for information and does not replace specialised medical or genetic advice.

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