• Disease Overview
  • Synonyms
  • Signs & Symptoms
  • Causes
  • Affected Populations
  • Disorders with Similar Symptoms
  • Diagnosis
  • Standard Therapies
  • Clinical Trials and Studies
  • References
  • Programs & Resources
  • Complete Report
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ASXL3-Related Disorder


Last updated: 6/5/2023
Years published: 2023


NORD gratefully acknowledges Meena Balasubramanian, MBBS, DCH, FRCPCH, MD, Sheffield Children’s NHS Foundation Trust, University of Sheffield, Sheffield, UK, for the preparation of this report.

Disease Overview

ASXL3-related disorder, also known as Bainbridge-Ropers syndrome, is a neurodevelopmental disorder that was first described by Bainbridge et al. in 2013. It is associated with changes (pathogenic variants or mutations) in the ASXL3 gene.

The initial description of this syndrome by Bainbridge et al. was based on four individuals with developmental delay, feeding difficulties, neurological abnormalities and difficulty gaining weight (failure to thrive). With the identification and publication of more patients, the spectrum of characteristics has expanded to include low muscle tone (hypotonia) (88%), characteristic facial features (92%), palate abnormalities (61%), musculoskeletal features (67%), behavioral issues (92%), crossed eyes (strabismus) (56%), sleep disturbance (50%) and autistic features (65%). Intellectual disability (or its precursor, global developmental delay) was noted in 95% of affected children.

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  • Bainbridge-Ropers syndrome
  • ASXL3 syndrome
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Signs & Symptoms

Developmental delay and intellectual disability

All patients described in the published literature, with sufficient clinical information to ascertain the level of delay in various developmental areas, had a speech and language delay. Some patients have been described with language regression as a child, and some patients have been described to communicate by alternate methods, such as Makaton signing. Developmental delay and intellectual disability ranged from mild to very severe.

Autism spectrum disorder (ASD) and other behavioral concerns

Autism diagnosis or autistic behaviors were described in 65% of individuals in the literature. Autistic traits included obsessions, inflexibility and incapacity for change, hand-flapping and rocking, and difficulties with sensory processing. Other behavioral difficulties described included self-injurious behaviors and aggression towards caregivers, emotional dysregulation with outbursts of either laughter, screaming, aggression and teeth grinding (bruxism).

Feeding issues

Feeding difficulties were described in 74% of individuals in the literature. Several presented with failure to thrive in infancy. Feeding difficulties included poor neonatal suck or latch, vomiting, gastroesophageal reflux, food refusal behaviors and requirement for assistance-feeding. Some babies required nasogastric tube insertion. There were reports of ongoing requirement for tube feeding in childhood. Some feeding difficulties in infancy were reported to improve with time.

Musculoskeletal features

Musculoskeletal features were seen in 67% of individuals reported in the literature. Many individuals had hypotonia (88%), which could have explained the accounts of wide range of movement (hypermobility). Other musculoskeletal features were accounted for by spine and thoracic wall abnormalities (scoliosis, kyphosis, pectus excavatum), digit and joint abnormalities (contractures, arachnodactyly, ulnar deviation, camptodactyly, overlapping digits) and foot abnormalities (pes planus, narrow feet, varus deformity).

A severe multi-joint condition of arthrogryposis multiplex congenita has been described in patients with pathogenic ASXL3 variants. There were reports of long slender hands and digits, and a long, thin body with long arms, legs, fingers and toes (Marfanoid body habitus).

Palate abnormalities were described in 61% of individuals in the literature; these were most often a high and narrow palate, but there was also a description of a submucous cleft . Despite the Marfanoid habitus, there have been no reports of children with a dilated aorta, as is associated with Marfan syndrome and other connective tissue disorders. One child with ASXL3-related disorder was found to have a subclavian artery aneurysm.

Facial features

Non-specific abnormal facial features have been described in most affected children (92%). There are no specific or defining facial features, but typical features included abnormal head shape, prominent forehead, highly arched eyebrows, eyebrows that meet in the center of the face (synophrys), widely spaced and deep-set eyes, down-slanting palpebral fissures, long and tubular nose, low-hanging columella, prominent nasal bridge, wide mouth, high arched palate, everted vermilion of the lower lip, small lower jaw (micrognathia), and crowded teeth, but these may not be recognized until after diagnosis. Additional dental abnormalities have also been reported, including large teeth, missing teeth and lack of enamel development (enamel hypoplasia).


Sleep disturbance was described in 50% of patients in the literature. This included reports of obstructive sleep apnea, poor sleep and easy waking. A report of rapid, deep breathing and slow, writhing movements (hyperventilation athetosis) was reportedly associated with the sleep-wake cycle, immediately prior to falling asleep.

Structural brain abnormalities

Structural brain abnormalities have been described, but are not as easily quantified, as MRI brain imaging is not routinely carried out unless there is a clinical indication. This may mean an under-reporting of brain abnormalities in the literature. Normal brain imaging was reported in most individuals, however there were some non-specific abnormalities such as white matter loss. One individual was reported to have normal early MRI scans but saw a clinical decline in correlation with subsequent cerebral and cerebellar atrophic changes. Cerebellar vermis hypoplasia has been described in some individuals.


Seizures or epilepsy have been described in 32% of individuals. A variety of seizure types have been reported in the literature, including generalized (tonic-clonic and absence), focal and complex focal seizures.

Variations of focal seizures have been described including atonic seizures (associated with other behaviors such as head-bobbing or spontaneous outbursts of laughter), myotonic seizures (with partial-body stiffness or shaking) and subclinical seizures.

A typical epilepsy was described, consisting of generalised epilepsy that starts in childhood, with absence seizures and tonic-clonic seizures. However, there have been reports of later-onset epilepsy starting during adulthood. Seizure frequency has been variably reported, with some individuals having sporadic and self-limiting epilepsy, some that resolved with treatment, and some individuals having up to 140 seizures a day despite treatment.

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ASXL3-related disorder is caused by pathogenic or likely pathogenic variants in the ASXL3 gene. The majority of variants are new mutations that result in a shortened protein product that does not function properly.

ASXL3-related disorder follows an autosomal dominant pattern of inheritance. Dominant genetic disorders occur when only a single copy of a mutated gene is necessary to cause the disease. The mutated gene can be inherited from either parent or can be the result of a changed gene in the affected individual. The risk of passing the mutated gene from an affected parent to a child is 50% for each pregnancy. The risk is the same for males and females.

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Affected populations

ASXL3-related disorder has been described all over the world and is not population specific.

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ASXL-related disorder may be suspected based on the signs and symptoms associated with the disorder. The diagnosis is confirmed with genomic testing that shows a pathogenic variant in the ASXL3 gene.

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Standard Therapies

Multidisciplinary care is recommended and includes management of multiple subspecialty appointments, equipment, medications and supplies. Ongoing assessment for palliative care involvement and/or home nursing is needed.

Developmental delay and intellectual disability should be managed by a developmental pediatrician. Speech and language delay should be managed by appropriate healthcare professionals.

Epilepsy should be treated with antiepileptic drugs (AEDs) by an experienced neurologist. Many different AEDs may be effective; no one AED has been demonstrated effective specifically for this disorder.

Poor weight gain and failure to thrive may require feeding therapy and gastrostomy tube placement for persistent feeding issues.

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Clinical Trials and Studies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

Some current clinical trials also are posted on the following page on the NORD website:

For information about clinical trials sponsored by private sources, contact:

For information about clinical trials conducted in Europe, contact:

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Schirwani S, Woods E, Koolen DA, et al. Familial Bainbridge-Ropers syndrome: Report of familial ASXL3 inheritance and a milder phenotype. Am J Med Genet A. 2023;191(1):29-36. https://doi.org/10.1002/ajmg.a.62981

Schirwani S, Albaba S, Carere DA, et al. Expanding the phenotype of ASXL3-related syndrome: A comprehensive description of 45 unpublished individuals with inherited and de novo pathogenic variants in ASXL3 [published correction appears in Am J Med Genet A. 2023 Jan;191(1):310]. Am J Med Genet A. 2021;185(11):3446-3458. https://doi.org/10.1002/ajmg.a.62465

Khan TR, Dolce A, Goodspeed K. A case of Bainbridge-Ropers syndrome with breath holding spells and intractable epilepsy: challenges in diagnosis and management. BMC Neurol. 2022;22(1):60. Published 2022 Feb 16. https://doi.org/10.1186/s12883-022-02573-w

Laquerriere A, Jaber D, Abiusi E, et al. Phenotypic spectrum and genomics of undiagnosed arthrogryposis multiplex congenita. J Med Genet. 2022;59(6):559-567. https://doi.org/10.1136/jmedgenet-2020-107595

Cuddapah VA, Dubbs HA, Adang L, et al. Understanding the phenotypic spectrum of ASXL-related disease: Ten cases and a review of the literature. Am J Med Genet A. 2021;185(6):1700-1711. https://doi.org/10.1002/ajmg.a.62156

Yu KP, Luk HM, Fung JLF, Chung BH, Lo IF. Further expanding the clinical phenotype in Bainbridge-Ropers syndrome and dissecting genotype-phenotype correlation in the ASXL3 mutational cluster regions. Eur J Med Genet. 2021;64(1):104107. https://doi.org/10.1016/j.ejmg.2020.104107

Schirwani S, Hauser N, Platt A, et al. Mosaicism in ASXL3-related syndrome: Description of five patients from three families. Eur J Med Genet. 2020;63(6):103925. https://doi.org/10.1016/j.ejmg.2020.103925

Myers KA, White SM, Mohammed S, et al. Childhood-onset generalized epilepsy in Bainbridge-Ropers syndrome [published correction appears in Epilepsy Res. 2018 Aug 10;:]. Epilepsy Res. 2018;140:166-170. doi:10.1016/j.eplepsyres.2018.01.014

Verhoeven W, Egger J, Räkers E, van Erkelens A, Pfundt R, Willemsen MH. Phenotypic characterization of an older adult male with late-onset epilepsy and a novel mutation in ASXL3 shows overlap with the associated Bainbridge-Ropers syndrome. Neuropsychiatr Dis Treat. 2018;14:867-870. Published 2018 Mar 27. https://doi.org/10.2147/NDT.S153511

Balasubramanian M, Willoughby J, Fry AE, et al. Delineating the phenotypic spectrum of Bainbridge-Ropers syndrome: 12 new patients with de novo, heterozygous, loss-of-function mutations in ASXL3 and review of published literature. J Med Genet. 2017;54(8):537-543. https://doi.org/10.1136/jmedgenet-2016-104360

Chinen Y, Nakamura S, Ganaha A, et al. Mild prominence of the Sylvian fissure in a Bainbridge-Ropers syndrome patient with a novel frameshift variant in ASXL3. Clin Case Rep. 2017;6(2):330-336. Published 2017 Dec 28. https://doi.org/10.1002/ccr3.1361

Dad R, Walker S, Scherer SW, Hassan MJ, Kang SY, Minassian BA. Hyperventilation-athetosis in ASXL3 deficiency (Bainbridge-Ropers) syndrome. Neurol Genet. 2017;3(5):e189. Published 2017 Sep 22. https://doi.org/10.1212/NXG.0000000000000189

Kuechler A, Czeschik JC, Graf E, et al. Bainbridge-Ropers syndrome caused by loss-of-function variants in ASXL3: a recognizable condition. Eur J Hum Genet. 2017;25(2):183-191. https://doi.org/10.1038/ejhg.2016.165

Srivastava A, Ritesh KC, Tsan YC, et al. De novo dominant ASXL3 mutations alter H2A deubiquitination and transcription in Bainbridge-Ropers syndrome. Hum Mol Genet. 2016;25(3):597-608. https://doi.org/10.1093/hmg/ddv499

Srivastava S, Cohen JS, Vernon H, et al. Clinical whole exome sequencing in child neurology practice. Ann Neurol. 2014;76(4):473-483. https://doi.org/10.1002/ana.24251

Bainbridge et al.: De novo truncating mutations in ASXL3 are associated with a novel clinical phenotype with similarities to Bohring-Opitz syndrome. Genome Medicine 2013 5:11. https://doi.org/10.1186/gm415

Balasubramanian M, Schirwani S. ASXL3-Related Disorder. 2020 Nov 5. In: Adam MP, Mirzaa GM, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK563693/ Accessed May 22, 2023.

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