From HPO
Homocystinuria- MedGen UID:
- 42485
- •Concept ID:
- C0019880
- •
- Disease or Syndrome
Homocystinuria is an inherited disorder in which the body is unable to process certain building blocks of proteins (amino acids) properly. \n\nThe most common form of homocystinuria, called classic homocystinuria, is characterized by tall stature, nearsightedness (myopia), dislocation of the lens at the front of the eye, a higher risk of blood clotting disorders, and brittle bones that are prone to fracture (osteoporosis) or other skeletal abnormalities. Some affected individuals also have developmental delay and learning problems.\n\nLess common forms of homocystinuria can cause intellectual disability, slower growth and weight gain (failure to thrive), seizures, and problems with movement. They can also cause and a blood disorder called megaloblastic anemia, which occurs when a person has a low number of red blood cells (anemia), and the remaining red blood cells are larger than normal (megaloblastic).\n\nThe signs and symptoms of homocystinuria typically develop during childhood, although some mildly affected people may not show signs and symptoms until adulthood.
Methylmalonic aciduria- MedGen UID:
- 343266
- •Concept ID:
- C1855119
- •
- Disease or Syndrome
Increased concentration of methylmalonic acid in the urine.
Dystonic disorder- MedGen UID:
- 3940
- •Concept ID:
- C0013421
- •
- Sign or Symptom
An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.
Lethargy- MedGen UID:
- 7310
- •Concept ID:
- C0023380
- •
- Sign or Symptom
A state of disinterest, listlessness, and indifference, resulting in difficulty performing simple tasks or concentrating.
Seizure- MedGen UID:
- 20693
- •Concept ID:
- C0036572
- •
- Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Global developmental delay- MedGen UID:
- 107838
- •Concept ID:
- C0557874
- •
- Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Spastic ataxia- MedGen UID:
- 376528
- •Concept ID:
- C1849156
- •
- Disease or Syndrome
Intellectual disability- MedGen UID:
- 811461
- •Concept ID:
- C3714756
- •
- Mental or Behavioral Dysfunction
Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.
Cerebral cortical atrophy- MedGen UID:
- 1646740
- •Concept ID:
- C4551583
- •
- Disease or Syndrome
Atrophy of the cortex of the cerebrum.
Megaloblastic anemia- MedGen UID:
- 1527
- •Concept ID:
- C0002888
- •
- Disease or Syndrome
Anemia characterized by the presence of erythroblasts that are larger than normal (megaloblasts).
Increased mean corpuscular volume- MedGen UID:
- 81303
- •Concept ID:
- C0302845
- •
- Finding
Larger than normal size of erythrocytes.
Hypotonia- MedGen UID:
- 10133
- •Concept ID:
- C0026827
- •
- Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Generalized hypotonia- MedGen UID:
- 346841
- •Concept ID:
- C1858120
- •
- Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Methylmalonic acidemia- MedGen UID:
- 120654
- •Concept ID:
- C0268583
- •
- Disease or Syndrome
For this GeneReview, the term "isolated methylmalonic acidemia" refers to a group of inborn errors of metabolism associated with elevated methylmalonic acid (MMA) concentration in the blood and urine that result from the failure to isomerize (convert) methylmalonyl-coenzyme A (CoA) into succinyl-CoA during propionyl-CoA metabolism in the mitochondrial matrix, without hyperhomocysteinemia or homocystinuria, hypomethioninemia, or variations in other metabolites, such as malonic acid. Isolated MMA is caused by complete or partial deficiency of the enzyme methylmalonyl-CoA mutase (mut0 enzymatic subtype or mut– enzymatic subtype, respectively), a defect in the transport or synthesis of its cofactor, 5-deoxy-adenosyl-cobalamin (cblA, cblB, or cblD-MMA), or deficiency of the enzyme methylmalonyl-CoA epimerase. Prior to the advent of newborn screening, common phenotypes included: Infantile/non-B12-responsive form (mut0 enzymatic subtype, cblB), the most common phenotype, associated with infantile-onset lethargy, tachypnea, hypothermia, vomiting, and dehydration on initiation of protein-containing feeds. Without appropriate treatment, the infantile/non-B12-responsive phenotype could rapidly progress to coma due to hyperammonemic encephalopathy. Partially deficient or B12-responsive phenotypes (mut– enzymatic subtype, cblA, cblB [rare], cblD-MMA), in which symptoms occur in the first few months or years of life and are characterized by feeding problems, failure to thrive, hypotonia, and developmental delay marked by episodes of metabolic decompensation. Methylmalonyl-CoA epimerase deficiency, in which findings range from complete absence of symptoms to severe metabolic acidosis. Affected individuals can also develop ataxia, dysarthria, hypotonia, mild spastic paraparesis, and seizures. In those individuals diagnosed by newborn screening and treated from an early age, there appears to be decreased early mortality, less severe symptoms at diagnosis, favorable short-term neurodevelopmental outcome, and lower incidence of movement disorders and irreversible cerebral damage. However, secondary complications may still occur and can include intellectual disability, tubulointerstitial nephritis with progressive impairment of renal function, "metabolic stroke" (bilateral lacunar infarction of the basal ganglia during acute metabolic decompensation), pancreatitis, growth failure, functional immune impairment, bone marrow failure, optic nerve atrophy, arrhythmias and/or cardiomyopathy (dilated or hypertrophic), liver steatosis/fibrosis/cancer, and renal cancer.
Hypomethioninemia- MedGen UID:
- 336368
- •Concept ID:
- C1848555
- •
- Finding
A decreased concentration of methionine in the blood.
Decreased circulating adenosylcobalamin concentration- MedGen UID:
- 336369
- •Concept ID:
- C1848556
- •
- Finding
The concentration of adenosylcobalam in the blood circulation is below the lower limit of normal. Adenosylcobalamin is one of the active forms of vitamin B12.
Decreased methylmalonyl-CoA mutase activity- MedGen UID:
- 336374
- •Concept ID:
- C1848579
- •
- Finding
An abnormality of Krebs cycle metabolism that is characterized by a decreased rate of methylmalonyl-CoA mutase activity.
Decreased methionine synthase activity- MedGen UID:
- 376395
- •Concept ID:
- C1848580
- •
- Finding
A reduction in methionine synthase activity.
Hyperhomocystinemia- MedGen UID:
- 812677
- •Concept ID:
- C3806347
- •
- Finding
An increased concentration of homocystine in the blood.
Decreased circulating methylcobalamin concentration- MedGen UID:
- 867371
- •Concept ID:
- C4021736
- •
- Finding
The concentration of methylcobalamin in the blood circulation is below the lower limit of normal. Methylcobalamin is a form of vitamin B12.
Nystagmus- MedGen UID:
- 45166
- •Concept ID:
- C0028738
- •
- Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
- Abnormality of blood and blood-forming tissues
- Abnormality of metabolism/homeostasis
- Abnormality of the eye
- Abnormality of the genitourinary system
- Abnormality of the musculoskeletal system
- Abnormality of the nervous system