National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Severe achondroplasia with developmental delay and acanthosis nigricans


Other Names:
SADDAN dysplasia; Skeleton skin brain syndrome; Severe achondroplasia with developmental delay and acanthosis nigricans; SADDAN dysplasia; Skeleton skin brain syndrome; Severe achondroplasia with developmental delay and acanthosis nigricans; SSB syndrome; SADDAN; Severe achondroplasia-developmental delay-acanthosis nigricans syndrome See More
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The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 85165

Definition
Severe achondroplasia-developmental delay-acanthosis nigricans syndrome is characterised by the association of severe achondroplasia with developmental delay and acanthosis nigricans. It has been described in four unrelated individuals. Structural central nervous system anomalies, seizures and hearing loss were also reported, together with bowing of the clavicle, femur, tibia and fibula in some cases. The syndrome is caused by a Lys650Met substitution in the kinase domain of fibroblast growth factor receptor 3 (encoded by the FGFR3 gene; 4p16.3).

Visit the Orphanet disease page for more resources.
Last updated: 2/1/2007

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Acanthosis nigricans
Darkened and thickened skin
0000956
Aplasia/Hypoplasia of the mandible 0009118
Brain atrophy
Brain degeneration
Brain wasting
[ more ] 		0012444
Enlarged cerebellum 0012081
Generalized-onset seizure 0002197
Hypoplasia of the corpus callosum
Underdevelopment of part of brain called corpus callosum
0002079
Intellectual disability, severe
Early and severe mental retardation
Mental retardation, severe
Severe mental retardation
[ more ] 		0010864
Metaphyseal chondrodysplasia 0005871
Severe global developmental delay 0011344
30%-79% of people have these symptoms
Abnormality of the clavicle
Abnormal collarbone
0000889
Femoral bowing
Bowed thighbone
0002980
Fibular bowing
Bowed calf bone
0010502
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ] 		0000252
Tibial bowing
Bowed shankbone
Bowed shinbone
[ more ] 		0002982
5%-29% of people have these symptoms
Congestive heart failure
Cardiac failure
Cardiac failures
Heart failure
[ more ] 		0001635
Exotropia
Outward facing eye ball
0000577
Gastroesophageal reflux
Acid reflux
Acid reflux disease
Heartburn
[ more ] 		0002020
High myopia
Severe near sightedness
Severely close sighted
Severely near sighted
[ more ] 		0011003
Pulmonary arterial hypertension
Increased blood pressure in blood vessels of lungs
0002092
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance 0000006
Central apnea 0002871
Depressed nasal bridge
Depressed bridge of nose
Flat bridge of nose
Flat nasal bridge
Flat, nasal bridge
Flattened nasal bridge
Low nasal bridge
Low nasal root
[ more ] 		0005280
Frontal bossing 0002007
Global developmental delay 0001263
Hearing impairment
Deafness
Hearing defect
[ more ] 		0000365
Hydrocephalus
Too much cerebrospinal fluid in the brain
0000238
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Kyphosis
Hunched back
Round back
[ more ] 		0002808
Lumbar hyperlordosis
Excessive inward curvature of lower spine
0002938
Megalencephaly 0001355
Mesomelia
Disproportionately short middle portion of limb
0003027
Midface retrusion
Decreased size of midface
Midface deficiency
Underdevelopment of midface
[ more ] 		0011800
Otitis media
Middle ear infection
0000388
Platyspondyly
Flattened vertebrae
0000926
Redundant skin
Loose redundant skin
Redundant skin folds
Sagging, redundant skin
[ more ] 		0001582
Rhizomelia
Disproportionately short upper portion of limb
0008905
Seizure 0001250
Severe short stature
Dwarfism
Proportionate dwarfism
Short stature, severe
[ more ] 		0003510
Sleep apnea
Pauses in breathing while sleeping
0010535
Wide anterior fontanel
Wider-than-typical soft spot of skull
0000260
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Last updated: 7/1/2020

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Severe achondroplasia with developmental delay and acanthosis nigricans. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Severe achondroplasia with developmental delay and acanthosis nigricans:
    International Skeletal Dysplasia Registry (ISDR)
     

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Severe achondroplasia with developmental delay and acanthosis nigricans. This website is maintained by the National Library of Medicine.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Severe achondroplasia with developmental delay and acanthosis nigricans. Click on the link to view a sample search on this topic.

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