The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
| Signs and Symptoms | Approximate number of patients (when available) |
| Aplasia/Hypoplasia of the cerebellum | 90% |
| Cerebral cortical atrophy | 90% |
| Hypertonia | 90% |
| Limitation of joint mobility | 90% |
| Microcephaly | 90% |
| Seizures | 90% |
| Deviation of finger | 50% |
| Abnormality of the foot | - |
| Ataxia | - |
| Autosomal recessive inheritance | - |
| Basal ganglia gliosis | - |
| Cerebellar hypoplasia | - |
| Congenital contracture | - |
| Congenital onset | - |
| Degeneration of anterior horn cells | - |
| EMG: neuropathic changes | - |
| Fasciculations | - |
| Feeding difficulties in infancy | - |
| Hyperreflexia | - |
| Hypoplasia of the pons | - |
| Hypoplasia of the ventral pons | - |
| Intellectual disability | - |
| Muscle weakness | - |
| Muscular hypotonia | - |
| Neuronal loss in basal ganglia | - |
| Progressive | - |
| Respiratory insufficiency | - |
| Spinal muscular atrophy | - |
A specific mutations in the VRK1 gene has caused PCH1 in at least one family.[1] Specific mutations in RARS2 and TSEN54 have also been associated with PCH1. TSEN54 mutations were identified in one case from a family with three siblings with PCH1; DNA was only available in one of the three siblings. Mutations in RARS2 were also identified in one case with PCH1.[3]
In general, there is no known genetic cause for the majority of PCH1 cases and no other genes have been linked to PCH1 yet, with the exception of rare cases associated with TSEN54, RARS2 and VRK1 mutations. In fact, only fifteen families with PCH1 have been published thus far; of these, mutations were only identified in 3 families. Further research on these and other candidate genes in PCH1 is necessary to identify mutations involved in the remaining majority of the PCH1 cases.[3]
Specific mutations in other genes have been shown to cause the various other forms of pontocerebellar hypoplasia and include the RARS2, TSEN2, TSEN34, and TSEN54 genes. Mutations in three related genes, TSEN2, TSEN34, and TSEN54, can result in PCH2.[1] TSEN54 gene mutations can also cause PCH4 and PCH5.[2951] Mutations in the RARS2 gene can cause PCH6. The genetic cause of PCH3 is unknown.[1]Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare 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.
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