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Disease Profile
Hypermethioninemia due to S-adenosylhomocysteine hydrolase deficiency
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
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Age of onset
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ICD-10
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Inheritance
Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.
Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.
X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.
Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.
Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.
Not applicable
Other names (AKA)
Psychomotor delay due to S-adenosylhomocysteine hydrolase deficiency; Psychomotor retardation due to S-adenosylhomocysteine hydrolase deficiency; Hypermethioninemia with deficiency of S-adenosylhomocysteine hydrolase
Categories
Congenital and Genetic Diseases; Nervous System Diseases
Summary
Hypermethioninemia due to S-adenosylhomocysteine hydrolase deficiency (SAHH deficiency) is a muscle disease associated with high blood levels of methionine and creatine kinase (CK). The main symptoms are psychomotor delay, behavioral disorders, severe myopathy, and delayed myelination from birth.
Symptoms
- Muscle disease (myopathy) with a blood exam showing an increase of the CK activity (in 100% of the reported cases)
Hypotonia Developmental delay - Behavioral disorders
- Very small head (
microcephaly ) - Myelination delay
Strabismus - Problems with blood coagulation
- Liver disease
Two sisters had fetal hydrops, brain anomalies and respiratory failure and death in early infancy. Also, a recent report described a 29 year old woman who had liver
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.
| Medical Terms | Other Names |
Learn More:
HPO ID
|
|---|---|---|
| 80%-99% of people have these symptoms | ||
| Elevated hepatic transaminase |
High liver enzymes
|
0002910 |
| Hyperhomocystinemia |
Elevated blood homocystine
|
0002160 |
| Hypoalbuminemia |
Low blood albumin
|
0003073 |
| 30%-79% of people have these symptoms | ||
| Abnormal facial shape |
Unusual facial appearance
|
0001999 |
| Cerebellar hypoplasia |
Small cerebellum
Underdeveloped cerebellum
[ more ] |
0001321 |
| 0003429 | ||
| Delayed myelination | 0012448 | |
|
Loss of developmental milestones
Mental deterioration in childhood
[ more ] |
0002376 | |
| Elevated coagulation factor V activity | 0011996 | |
| Elevated serum creatine kinase |
Elevated blood creatine phosphokinase
Elevated circulating creatine phosphokinase
Elevated creatine kinase
Elevated serum CPK
Elevated serum creatine phosphokinase
High serum creatine kinase
Increased CPK
Increased creatine kinase
Increased creatine phosphokinase
Increased serum CK
Increased serum creatine kinase
Increased serum creatine phosphokinase
[ more ] |
0003236 |
| Esotropia |
Inward turning cross eyed
|
0000565 |
| Failure to thrive |
Faltering weight
Weight faltering
[ more ] |
0001508 |
| Global developmental delay | 0001263 | |
| Growth delay |
Delayed growth
Growth deficiency
Growth failure
Growth retardation
Poor growth
Retarded growth
[ more ] |
0001510 |
| Hydrops fetalis | 0001789 | |
| Hyperintensity of cerebral white matter on |
0030890 | |
| Hypofibrinogenemia | 0011900 | |
| Hypoplasia of the |
Underdevelopment of part of brain called corpus callosum
|
0002079 |
| Hypoplasia of the pons | 0012110 | |
| Infantile muscular hypotonia |
Decreased muscle tone in infant
|
0008947 |
| Muscular dystrophy | 0003560 | |
| Poor head control | 0002421 | |
| Prolonged prothrombin time | 0008151 | |
| Reduced antithrombin III activity | 0001976 | |
| Reduced factor VII activity | 0008169 | |
| Short attention span |
Poor attention span
Problem paying attention
[ more ] |
0000736 |
| 5%-29% of people have these symptoms | ||
| Abnormality of hair texture | 0010719 | |
| Abnormality of the dentition |
Abnormal dentition
Abnormal teeth
Dental abnormality
[ more ] |
0000164 |
|
Disease of the heart muscle
|
0001638 | |
| Hepatocellular carcinoma | 0001402 | |
| Hypermethioninemia |
Increased methionine in blood
|
0003235 |
| Microcephaly |
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ] |
0000252 |
| Pes planus |
Flat feet
Flat foot
[ more ] |
0001763 |
| Respiratory failure | 0002878 | |
| Sensorimotor neuropathy |
Nerve damage causing decreased feeling and movement
|
0007141 |
| Ventriculomegaly | 0002119 | |
| Widened subarachnoid space | 0012704 | |
| Percent of people who have these symptoms is not available through HPO | ||
| 0000007 | ||
|
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] |
0001249 | |
| Motor delay | 0001270 | |
Treatment
Treatment may include:[2]
- A low methionine diet: This can decrease and sometimes even normalize the abnormalities in the blood exams. Patients have to be on a
protein restricted diet and supplemented with a methionine-freeamino acid mixture. - Supplementation with phosphatidylcholine and creatine: At this time there is no evidence that this treatment is effective.
- Liver transplantation: Recently, liver transplantation was successfully done in one girl at the age of 40 months, but longer follow-up is needed to know the outcome of the liver transplantation.
The treatment outcome depends on the severity of the disease. It is not known whether even early intervention could help in severe cases. In others, it is possible that earlier initiation of treatment may improve the outcome. Regular careful evaluation of all body systems is indicated, mainly of the nervous system, psychomotor development, muscles, liver and blood (for coagulation). This includes
Learn more
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
- 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.
References
- Hypermethioninemia. Genetics Home Reference:. April, 2007; https://ghr.nlm.nih.gov/condition/hypermethioninemia.
- Baric I. Consensus recommendations for the diagnosis, treatment and follow-up of inherited methylation disorders. J Inherit Metab Dis. September 26, 2016; https://www.ncbi.nlm.nih.gov/pubmed/27671891.
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