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

Microhydranencephaly


Other Names:
MHAC; Hydranencephaly and microcephaly
Categories:
Microhydranencephaly is a developmental abnormality that affects the brain. Signs and symptoms may include extreme microcephaly, scalp rugae (a series of ridges), profound developmental delay and severe intellectual disability. Imaging studies of the brain generally reveal incomplete brain formation and severe hydrocephalus (accumulation of fluid in the brain). In most cases, the underlying cause is unknown. Rarely, the condition is caused by changes (mutations) in the NDE1 gene and is inherited in an autosomal recessive manner. Treatment is based on the signs and symptoms present in each person.[1][2][3]
Last updated: 10/1/2015
Microhydranencephaly is a developmental abnormality that affects the brain. Signs and symptoms can vary but generally include:[3][2][1]
  • Extreme microcephaly
  • Scalp rugae (a series of ridges)
  • Profound developmental delay
  • Severe intellectual disability
  • Spasticity

Imaging studies of the brain generally reveal incomplete brain formation and severe hydrocephalus (accumulation of fluid in the brain).[3][1]
Last updated: 10/1/2015

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.

Showing of 24 |
Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Agenesis of corpus callosum 0001274
Athetosis
Involuntary writhing movements in fingers, hands, toes, and feet
0002305
Autosomal recessive inheritance 0000007
Cerebellar hypoplasia
Small cerebellum
Underdeveloped cerebellum
[ more ] 		0001321
Generalized myoclonic seizure 0002123
Hydranencephaly 0002324
Hyperreflexia
Increased reflexes
0001347
Hypoplasia of the brainstem
Small brainstem
Underdeveloped brainstem
[ more ] 		0002365
Intellectual disability, progressive
Mental retardation, progressive
Progressive mental retardation
[ more ] 		0006887
Intellectual disability, severe
Early and severe mental retardation
Mental retardation, severe
Severe mental retardation
[ more ] 		0010864
Macrotia
Large ears
0000400
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ] 		0000252
Multiple joint contractures 0002828
Pachygyria
Fewer and broader ridges in brain
0001302
Profound global developmental delay 0012736
Prominent nasal bridge
Elevated nasal bridge
High nasal bridge
Prominent bridge of nose
Prominent nasal root
Protruding bridge of nose
Protruding nasal bridge
[ more ] 		0000426
Proptosis
Bulging eye
Eyeballs bulging out
Prominent eyes
Prominent globes
Protruding eyes
[ more ] 		0000520
Self-mutilation
Deliberate self-harm
Self mutilation
[ more ] 		0000742
Short stature
Decreased body height
Small stature
[ more ] 		0004322
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting
[ more ] 		0003202
Sloping forehead
Inclined forehead
Receding forehead
[ more ] 		0000340
Spastic tetraplegia 0002510
Talipes equinovarus
Club feet
Club foot
Clubfeet
Clubfoot
[ more ] 		0001762
Ventriculomegaly 0002119
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Last updated: 7/1/2020
In many cases, the exact, underlying cause of microhydranencephaly is unknown. There are reports of families in which the condition is caused by changes (mutations) in the NDE1 gene. In these rare cases, more than one family member (often a pair of siblings) had the condition.[1][3]
Last updated: 10/1/2015
Most cases of microhydranencephaly occur sporadically in people with no family history of the condition. However, the condition can rarely affect more than one family member and be inherited in an autosomal recessive manner.[1][3] In these cases, an affected person must have a mutation in both copies of the responsible gene in each cell. The parents of an affected person usually each carry one mutated copy of the gene and are referred to as carriers. Carriers typically do not have signs or symptoms of the condition. When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) chance to have the condition, a 50% (1 in 2) chance to be a carrier like each of the parents, and a 25% chance to not have the condition and not be a carrier.
Last updated: 10/1/2015
A diagnosis of microhydranencephaly is generally suspected based on the presence of characteristic signs and symptoms. Additional testing can then be ordered to confirm the diagnosis. This generally consists of imaging studies to evaluate the brain for structural abnormalities and severe hydrocephalus (accumulation of fluid in the brain).[2]
Last updated: 10/1/2015

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

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.

Clinical Research Resources

  • The Centers for Mendelian Genomics program is working to discover the causes of rare genetic disorders. For more information about applying to the research study, please visit their website.

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.

In-Depth Information

  • 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. 
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Microhydranencephaly. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Guven A, Gunduz A, Bozoglu TM, Yalcinkaya C, Tolun A. Novel NDE1 homozygous mutation resulting in microhydranencephaly and not microlyssencephaly. Neurogenetics. August 2012; 13(3):189-194.
  2. Behunova J, Zavadilikova E, Bozoglu TM, Gunduz A, Tolun A, Yalcinkaya C. Familial microhydranencephaly, a family that does not map to 16p13.13-p12.2: relationship with hereditary fetal brain degeneration and fetal brain disruption sequence. Clin Dysmorphol. July 2010; 19(3):107-118.
  3. Marla J. F. O'Neill. MICROHYDRANENCEPHALY. OMIM. April 2014; http://omim.org/entry/605013.