- Hyperhomocystinemia (HP:0002160): An increased concentration of homocystine in the blood. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:88618)
- Elevated circulating hepatic transaminase concentration (HP:0002910): Elevations of the levels of SGOT and SGPT in the serum. SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) are transaminases primarily found in the liver and heart and are released into the bloodstream as the result of liver or heart damage. SGOT and SGPT are used clinically mainly as markers of liver damage. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:88618)
- Hypoalbuminemia (HP:0003073): The concentration of albumin in the blood circulation is below the lower limit of normal. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:88618)
- Abnormal circulating methionine concentration (HP:0010901): Any deviation from the normal concentration of methionine in the blood circulation. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:88618)
- Abnormal circulating homocysteine concentration (HP:0010919): An abnormality of a homocysteine metabolic process. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:88618)
- Strabismus (HP:0000486): A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Esotropia (HP:0000565): A form of strabismus with one or both eyes turned inward ('crossed') to a relatively severe degree, usually defined as 10 diopters or more. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Atypical behavior (HP:0000708): Atypical behavior is an abnormality in a person's actions that can be controlled or modulated by the will of the individual. While abnormal behaviors can be difficult to control, they are distinct from other abnormal actions that cannot be affected by the individual's will. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Short attention span (HP:0000736): Reduced attention span characterized by distractibility and impulsivity. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Global developmental delay (HP:0001263): 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. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Cerebellar hypoplasia (HP:0001321): Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Abnormality of the liver (HP:0001392): An abnormality of the liver. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Hydrops fetalis (HP:0001789): The abnormal accumulation of fluid in two or more fetal compartments, including ascites, pleural effusion, pericardial effusion, and skin edema. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Abnormality of coagulation (HP:0001928): An abnormality of the process of blood coagulation. That is, altered ability or inability of the blood to clot. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Reduced antithrombin III activity (HP:0001976): An abnormality of coagulation related to a decreased concentration of antithrombin-III. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Abnormal facial shape (HP:0001999): An abnormal morphology (form) of the face or its components. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Poor head control (HP:0002421): Difficulty to maintain correct position of the head while standing or sitting. Infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk. Several articles have maintained that head lag should be absent by age 3 to 4 months. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Elevated circulating creatine kinase activity (HP:0003236): The activity of creatine kinase in the blood circulation is above the upper limit of normal. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- CNS hypomyelination (HP:0003429): Reduced amount of myelin in the central nervous system resulting from defective myelinogenesis. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Muscular dystrophy (HP:0003560): The term dystrophy means abnormal growth. However, muscular dystrophy is used to describe primary myopathies with a genetic basis and a progressive course characterized by progressive skeletal muscle weakness and wasting, defects in muscle proteins, and histological features of muscle fiber degeneration (necrosis) and regeneration. If possible, it is preferred to use other HPO terms to describe the precise phenotypic abnormalities. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Prolonged prothrombin time (HP:0008151): Increased time to coagulation in the prothrombin time test, which is a measure of the extrinsic pathway of coagulation. The results of the prothrombin time test are often expressed in terms of the International normalized ratio (INR), which is calculated as a ratio of the patient's prothrombin time (PT) to a control PT standardized for the potency of the thromboplastin reagent developed by the World Health Organization (WHO) using the formula: INR is equal to Patient PT divided by Control PT. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Reduced factor VII activity (HP:0008169): Reduced activity of coagulation factor VII. Factor VII is part of the extrinsic coagulation pathway, which is initiated at the site of injury in response to the release of tissue factor (fIII). Tissue factor and activated factor VII catalyze the activation of factor X. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Floppy infant (HP:0008947): Floppiness/hypotonia is defined as reduced resistance to passive movement of joints. Physical examination of floppy/hypotonic infants shows head lag, lack of shoulder and elbow muscle contraction on traction response, inability to tighten the shoulder girdle muscles (or slipping through) when held under the axillae, scarf sign (when the arm is pulled to the opposite side, the arm wraps around the neck with the elbow crossing midline), hyperdorsiflexion of the feet, easy apposition of the thumb against the forearm, feet touching the cheek with ease and without discomfort, frog leg position, and inverted U sign on ventral suspension (head, arms, and legs hanging down without elbow or knee flexion and the trunk rounded in a dome shape). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Hypofibrinogenemia (HP:0011900): Decreased concentration of fibrinogen in the blood. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Elevated coagulation factor V activity (HP:0011996): Increased activity of coagulation factor V, Factor V, which is activated to factor Va by means of minute amounts of thrombin (and inactivated by larger amounts of thrombin). Activated factor V (fVa) is a cofactor in the formation of the prothrombinase complex. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Hypoplasia of the pons (HP:0012110): Underdevelopment of the pons. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Delayed myelination (HP:0012448): Delayed myelination. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Hyperintensity of cerebral white matter on MRI (HP:0030890): A brighter than expected signal on magnetic resonance imaging emanating from the cerebral white matter. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:88618)
- Abnormality of the dentition (HP:0000164): Any abnormality of the teeth. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Hepatocellular carcinoma (HP:0001402): A kind of neoplasm of the liver that originates in hepatocytes and presents macroscopically as a soft and hemorrhagic tan mass in the liver. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Cardiomyopathy (HP:0001638): A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Pes planus (HP:0001763): A foot where the longitudinal arch of the foot is in contact with the ground or floor when the individual is standing; or, in a patient lying supine, a foot where the arch is in contact with the surface of a flat board pressed against the sole of the foot by the examiner with a pressure similar to that expected from weight bearing; or, the height of the arch is reduced. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Respiratory failure (HP:0002878): A severe form of respiratory insufficiency characterized by inadequate gas exchange such that the levels of oxygen or carbon dioxide cannot be maintained within normal limits. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Hypermethioninemia (HP:0003235): An increased concentration of methionine in the blood. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Sensorimotor neuropathy (HP:0007141). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Abnormality of hair texture (HP:0010719): An abnormality of the texture of the hair. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
- Widened subarachnoid space (HP:0012704): An increase in size of the anatomic space between the arachnoid membrane and pia mater. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:88618)
These phenotypes are associated with the disease S-adenosylhomocysteine hydrolase deficiency (ORPHA:88618).