Condition group
Inherited metabolic disorders
Inherited metabolic disorders are genetic conditions that disrupt how the body breaks down or processes substances. The library has guides to 23 of them, including late-infantile metachromatic leukodystrophy (MLD), infantile Krabbe disease and Hurler syndrome (severe MPS I). Of these 23, 7 have a donor transplant as an established option for selected patients, 2 have cell or gene therapies that may be options for eligible patients in some countries, 12 are usually treated without a transplant and 2 are not treated with transplant.
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23 conditions6 diagnosis guides
Start with the name you were given
Diagnosis guides for inherited metabolic disorders
Some diagnoses cover several subtypes. These guides explain how they fit together.
23 conditions compared
Who do inherited metabolic disorders affect, and where does transplant fit?
| Condition | Who it affects | How it is passed on | Where transplant fits |
|---|---|---|---|
| Donor transplant option7 conditions | |||
| Cerebral adrenoleukodystrophy (cALD)Cerebral ALD is an inherited condition in which inflammation damages the protective coating on nerves in the brain. This can cause a loss of skills over time. | Cerebral disease often affects boys but can also begin later in life. The broader X-ALD spectrum includes conditions with different treatment needs. | X-linked | A donor transplant can slow early disease in suitable patients. In the US, some without a matched donor may have gene therapy with their own cells, which carries a blood cancer risk. |
| Hunter syndrome (MPS II)Hunter syndrome (MPS II) is an inherited condition that almost always affects boys. Sugar chains build up and harm the airway, heart, joints and, in the severe form, the brain. | Almost always boys; signs usually appear between 18 months and 4 years of age. | X-linked | A donor stem cell transplant is used for some young boys, mostly before brain changes begin. Experts do not all agree on when it should be used. |
| Hurler syndrome (severe MPS I)Hurler syndrome is the severe form of MPS I, an inherited condition. Certain sugar molecules build up and can affect development, bones, joints, heart, breathing, hearing and vision. | Severe MPS I becomes apparent in early childhood, sometimes following newborn screening or family testing. | Autosomal recessive | For suitable young children, a donor stem cell transplant is an established treatment that can slow brain decline. An unrelated donor or cord blood can be an option. |
| Infantile Krabbe diseaseInfantile Krabbe disease is a genetic condition that damages the protective coating on nerves in the brain and body. It can get worse quickly in babies. | An early-onset Krabbe phenotype in infancy; a low enzyme-screening result alone does not predict every infant’s course. | Autosomal recessive | A donor stem cell transplant can improve outcomes when done very early, ideally before symptoms. It does not guarantee normal development or undo advanced damage. |
| Late-infantile and juvenile Krabbe diseaseLate-infantile and juvenile Krabbe disease is a genetic condition that damages the coating on nerves after early infancy. This can affect walking, vision, coordination and other skills. | Begins later in infancy or childhood; age categories do not perfectly predict the disease course. | Autosomal recessive | A stem cell transplant from a related or unrelated donor may be considered before major decline. The benefit depends on the stage and pace of the disease. |
| Late-juvenile metachromatic leukodystrophy (MLD)Late-juvenile MLD is an inherited condition that starts later in childhood and damages the coating on nerves. It can affect learning, behavior and walking. | Begins later in childhood than early-juvenile MLD. Rate of progression and function at assessment vary. | Autosomal recessive | A donor stem cell transplant may help selected people before or very early in symptoms. The donor can be unrelated, and the aim is to keep function. |
| Severe infantile osteopetrosis (ARO)Severe infantile osteopetrosis is a genetic condition that makes bones too dense, so they can crowd the marrow and press on nerves. The old word “malignant” does not mean cancer. | Severe recessive forms often become apparent in infancy, although osteopetrosis as a whole includes several distinct disorders. | Autosomal recessive | A donor stem cell transplant can help in forms that respond to it, but nerve damage may remain. Genetic testing matters first, because a transplant is not right for every type. |
| Cell or gene therapy options2 conditions | |||
| Early-juvenile metachromatic leukodystrophy (MLD)Early-juvenile MLD is a childhood form of an inherited condition that damages the protective coating on nerves. As a result, movement, learning and other brain skills can get worse. | An early-childhood presentation within the wider MLD spectrum; clinical stage is as important as the age-based subtype label. | Autosomal recessive | Gene therapy with a child’s own cells is approved for early cases in the European Union, the UK and the US. A donor transplant may be considered for some children early on. |
| Late-infantile metachromatic leukodystrophy (MLD)Late-infantile MLD is a fast-moving inherited condition in young children. It damages the protective coating on nerves, affecting movement and other brain functions. | The late-infantile form becomes symptomatic in early childhood; a family diagnosis can sometimes identify an affected sibling before symptoms. In the US, MLD was added to the recommended newborn screening panel in December 2025, but states are not required to begin screening right away. | Autosomal recessive | Approved gene therapy uses the child’s own cells, so no registry donor is needed. A donor transplant is generally not recommended for this form because it works too slowly. |
| Limited transplant role12 conditions | |||
| Adult-onset metachromatic leukodystrophy (MLD)Adult-onset MLD is an inherited condition that damages the protective coating on nerves. It may first show up as changes in behavior, thinking or movement. | Begins in later adolescence or adulthood, with a variable course and sometimes delayed recognition. | Autosomal recessive | A donor stem cell transplant may be considered only for carefully selected people before major decline. It cannot reliably undo damage already done. |
| Alpha-mannosidosisAlpha-mannosidosis is a genetic condition in which certain sugar-containing molecules build up. It can affect hearing, learning, bones, movement and the immune system. | Features usually develop in childhood, but milder disease may be recognized later. | Autosomal recessive | A donor stem cell transplant has been used in a small number of people, mostly young children before major decline. It may not reverse every nerve or bone problem. |
| Farber disease (acid ceramidase deficiency)Farber disease is a very rare inherited condition in which fats called ceramides build up. It often causes painful joints, lumps under the skin and a hoarse voice. | Signs usually begin in infancy, in boys and girls alike. Milder forms may not be recognized until later childhood or adulthood. | Autosomal recessive | A donor stem cell transplant has helped the joint problems and lumps under the skin in a small number of children. It has not stopped damage to the brain and nerves. |
| FucosidosisFucosidosis is a genetic enzyme condition in which certain molecules build up. It can affect development, movement, breathing, hearing, skin and bones. | Usually presents during childhood, with a range of severity and progression. | Autosomal recessive | A donor stem cell transplant has been tried in very few patients. It may be considered before major brain decline, but it is not a routine treatment. |
| Gaucher disease type 1In type 1, a fatty substance builds up in the spleen, liver and bones. It usually does not affect the brain. | Can begin at any age from childhood to adulthood, and some people never have symptoms. In France, symptoms typically begin around age 15 and diagnosis comes around age 22 (French national protocol, 2025). More common in people of Ashkenazi Jewish heritage. | Autosomal recessive | A donor stem cell transplant can correct it, but it is now rarely used, because the medicines work without a transplant’s serious risks. |
| Gaucher disease type 3Gaucher disease type 3 is a genetic condition that can affect blood counts, the liver, spleen and bones. It can also slowly affect the brain and nerves. | Often recognized in childhood, with variable neurologic progression and systemic severity. | Autosomal recessive | A donor stem cell transplant is used only in rare, carefully chosen cases. It may help blood and body problems, but it is not a dependable cure for brain symptoms. |
| I-cell disease (mucolipidosis II)I-cell disease is a severe genetic condition that keeps several enzymes from reaching the right place in cells. It can cause bone, growth, heart and breathing problems early in life. | Features are often present at or near birth. This severe form differs from mucolipidosis III and intermediate GNPTAB-related disease. | Autosomal recessive | Donor stem cell transplants have been reported, but they are not routine treatment. They have not shown a predictable benefit for survival or development. |
| Maroteaux-Lamy syndrome (MPS VI)Maroteaux-Lamy syndrome (MPS VI) is a rare inherited condition. A missing enzyme lets sugar chains build up and harm bones, joints, heart valves, airways and eyes, but usually not thinking. | Signs usually begin in early childhood. Rapidly progressing forms appear before age 2, while slowly progressing forms may not be diagnosed until later childhood or adulthood. Reported birth prevalence ranges from about 1 in 43,000 (Turkish immigrants in Germany) to about 1 in 1.5 million (Sweden). | Autosomal recessive | A donor stem cell transplant is used for some children, mostly when enzyme therapy has failed or is not available. Its balance of benefits and risks is less clear than in other types of MPS. |
| Niemann-Pick disease type C2 (NPC2)Niemann-Pick disease type C2 is a genetic condition that disrupts how cells move fats. It can affect the liver, spleen, lungs and nervous system. | Presentation can range from infancy to later life. Severe early lung disease is an important possible feature, not a universal presentation. | Autosomal recessive | Donor transplants have been reported in only a few isolated cases, so they are not routine care. A registry donor is not the usual treatment path. |
| Niemann-Pick disease types A and B (ASMD)Acid sphingomyelinase deficiency (ASMD) is also called Niemann-Pick disease types A, A/B and B. It is an inherited condition in which a fat builds up in the liver, spleen, lungs and sometimes the brain. | Type A usually shows as a large liver and spleen by about 3 months of age. Types A/B and B can appear from early childhood to adulthood. ASMD occurs worldwide; some gene changes are more common in certain groups, such as Ashkenazi Jewish people, where an estimated 1 in 100 to 1 in 200 carry one (2023 international guideline). | Autosomal recessive | Donor stem cell transplants were tried before enzyme therapy, but they did not protect the brain. They are rarely used now, so a registry donor is not the usual path. |
| Sly syndrome (MPS VII)Sly syndrome (MPS VII) is an extremely rare inherited condition. A missing enzyme lets sugar chains build up, and some babies are very ill before birth. | MPS VII can start before birth: 23 of 56 people in a 2016 international survey had a history of hydrops fetalis. Others show signs in infancy or early childhood, and rare people with milder disease have lived into their forties. | Autosomal recessive | A donor stem cell transplant has been used in only a few children, with mixed results. When considered, it is decided case by case, ideally early. |
| Wolman disease (infantile-onset LAL deficiency)Wolman disease is a rare inherited condition in babies. A missing enzyme lets fats build up in the liver, spleen, gut and other organs. | Babies, boys and girls alike, with signs in the first weeks of life. It is inherited in an autosomal recessive pattern. | Autosomal recessive | Experts decide case by case whether a child later has a donor transplant. The donor may be a relative, an unrelated volunteer or cord blood. |
| Not treated with transplant2 conditions | |||
| Gaucher disease type 2Gaucher disease type 2 is a rare inherited condition. It affects a baby’s brain and nerves in the first months of life and gets worse quickly. | Babies, in every ethnic group. Signs usually begin in the first months of life and sometimes before birth. In the international RETRIEVE study (sites in 10 countries, data collected 2019–2021), the median age at the first neurological sign was 4 months and at diagnosis 8 months. | Autosomal recessive | Transplant is not a treatment for type 2. French national guidance says no specific treatment exists. |
| Niemann-Pick disease type C1 (NPC1)Niemann-Pick disease type C1 is a rare genetic condition in which cells cannot move cholesterol and other fats. It slowly harms the brain and nerves and can affect the liver and spleen. | Can begin at any age, from before birth to adulthood; people whose symptoms start as adults may be up to a third of all cases. Found worldwide. | Autosomal recessive | A donor stem cell transplant has not been shown to slow the brain and nerve disease of NPC1, and it is not part of care. A registry donor is not the treatment path. |
Treatment depends on the exact diagnosis, disease stage, prior treatment and the person’s health.
Ways to help
Understanding can become action.
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