Citrullinemia type I (CTLN1) presents as a spectrum that includes a neonatal acute form (the "classic" form), a milder late-onset form (the "non-classic" form), a form in which women have onset of symptoms at pregnancy or post partum, and a form without symptoms or hyperammonemia. Distinction between the forms is based primarily on clinical findings, although emerging evidence suggests that measurement of residual argininosuccinate synthase enzyme activity may help to predict those who are likely to have a severe phenotype and those who are likely to have an attenuated phenotype. Infants with the acute neonatal form appear normal at birth. Shortly thereafter, they develop hyperammonemia and become progressively lethargic, feed poorly, often vomit, and may develop signs of increased intracranial pressure (ICP). Without prompt intervention, hyperammonemia and the accumulation of other toxic metabolites (e.g., glutamine) result in increased ICP, increased neuromuscular tone, spasticity, ankle clonus, seizures, loss of consciousness, and death. Children with the severe form who are treated promptly may survive for an indeterminate period of time, but usually with significant neurologic deficits. Even with chronic protein restriction and scavenger therapy, long-term complications such as liver failure and other (rarely reported) organ system manifestations are possible. The late-onset form may be milder than that seen in the acute neonatal form, but commences later in life for reasons that are not completely understood. The episodes of hyperammonemia are similar to those seen in the acute neonatal form, but the initial neurologic findings may be more subtle because of the older age of the affected individuals. Women with onset of severe symptoms including acute hepatic decompensation during pregnancy or in the postpartum period have been reported. Furthermore, previously asymptomatic and non-pregnant individuals have been described who remained asymptomatic up to at least age ten years, with the possibility that they could remain asymptomatic lifelong. [from GeneReviews]

HFE hemochromatosis is characterized by inappropriately high absorption of iron by the small intestinal mucosa. The phenotypic spectrum of HFE hemochromatosis includes: Persons with clinical HFE hemochromatosis, in whom manifestations of end-organ damage secondary to iron overload are present; Individuals with biochemical HFE hemochromatosis, in whom transferrin-iron saturation is increased and the only evidence of iron overload is increased serum ferritin concentration; and Non-expressing p.Cys282Tyr homozygotes, in whom neither clinical manifestations of HFE hemochromatosis nor iron overload are present. Clinical HFE hemochromatosis is characterized by excessive storage of iron in the liver, skin, pancreas, heart, joints, and anterior pituitary gland. In untreated individuals, early symptoms include: abdominal pain, weakness, lethargy, weight loss, arthralgias, diabetes mellitus; and increased risk of cirrhosis when the serum ferritin is higher than 1,000 ng/mL. Other findings may include progressive increase in skin pigmentation, congestive heart failure, and/or arrhythmias, arthritis, and hypogonadism. Clinical HFE hemochromatosis is more common in men than women. [from GeneReviews]

A maple syrup urine disease caused by mutations in BCKDHA. [from MONDO]

Factor V Leiden thrombophilia is characterized by a poor anticoagulant response to activated protein C (APC) and an increased risk for venous thromboembolism (VTE). Deep vein thrombosis (DVT) is the most common VTE, with the legs being the most common site. Thrombosis in unusual locations is less common. Evidence suggests that heterozygosity for the Leiden variant has at most a modest effect on risk for recurrent thrombosis after initial treatment of a first VTE. It is unlikely that factor V Leiden thrombophilia (i.e., heterozygosity or homozygosity for the Leiden variant) is a major factor contributing to pregnancy loss and other adverse pregnancy outcomes (preeclampsia, fetal growth restriction, and placental abruption). The clinical expression of factor V Leiden thrombophilia is influenced by the following: The number of Leiden variants (heterozygotes have a slightly increased risk for venous thrombosis; homozygotes have a much greater thrombotic risk). Coexisting genetic thrombophilic disorders, which have a supra-additive effect on overall thrombotic risk. Acquired thrombophilic disorders: antiphospholipid antibody (APLA) syndrome, paroxysmal nocturnal hemoglobinuria, myeloproliferative disorders, and increased levels of clotting factors. Circumstantial risk factors including but not limited to pregnancy, central venous catheters, travel, combined oral contraceptive (COC) use and other combined contraceptives, oral hormone replacement therapy (HRT), selective estrogen receptor modulators (SERMs), obesity, leg injury, and advancing age. [from GeneReviews]

Failure to meet, or late achievement of developmental milestones. [from NCI]

An abnormality of coagulation associated with an increased risk of thrombosis. [from HPO]

Hyperlysinemia type I is an autosomal recessive metabolic condition with variable clinical features. Some patients who present in infancy with nonspecific seizures, hypotonia, or mildly delayed psychomotor development have been found to have increased serum lysine and pipecolic acid on laboratory analysis. However, about 50% of probands are reported to be asymptomatic, and hyperlysinemia is generally considered to be a benign metabolic variant (summary by Tondo et al., 2013; Houten et al., 2013). The AASS gene encodes a bifunctional enzyme: lysine alpha-ketoglutarate reductase and saccharopine dehydrogenase. In hyperlysinemia type I, both enzymatic functions of AASS are defective; in hyperlysinemia type II, also known as saccharopinuria (268700), some of the first enzymatic function is retained (Cox, 1985; Cox et al., 1986). [from OMIM]

Arginase deficiency in untreated individuals is characterized by episodic hyperammonemia of variable degree that is infrequently severe enough to be life threatening or to cause death. Most commonly, birth and early childhood are normal. Untreated individuals have slowing of linear growth at age one to three years, followed by development of spasticity, plateauing of cognitive development, and subsequent loss of developmental milestones. If untreated, arginase deficiency usually progresses to severe spasticity, loss of ambulation, complete loss of bowel and bladder control, and severe intellectual disability. Seizures are common and are usually controlled easily. Individuals treated from birth, either as a result of newborn screening or having an affected older sib, appear to have minimal symptoms. [from GeneReviews]

An increased concentration of alanine in the blood. [from HPO]

Untreated tyrosinemia type I usually presents either in young infants with severe liver involvement or later in the first year with liver dysfunction and renal tubular dysfunction associated with growth failure and rickets. Untreated children may have repeated, often unrecognized, neurologic crises lasting one to seven days that can include change in mental status, abdominal pain, peripheral neuropathy, and/or respiratory failure requiring mechanical ventilation. Death in the untreated child usually occurs before age ten years, typically from liver failure, neurologic crisis, or hepatocellular carcinoma. Combined treatment with nitisinone and a low-tyrosine diet has resulted in a greater than 90% survival rate, normal growth, improved liver function, prevention of cirrhosis, correction of renal tubular acidosis, and improvement in secondary rickets. [from GeneReviews]

Tyrosinemia type II (TYRSN2) is an autosomal recessive disorder characterized by keratitis, painful palmoplantar hyperkeratosis, mental retardation, and elevated serum tyrosine levels. The disorder is caused by deficiency of hepatic tyrosine aminotransferase (Natt et al., 1992). [from OMIM]

Angelman syndrome (AS) is characterized by severe developmental delay or intellectual disability, severe speech impairment, gait ataxia and/or tremulousness of the limbs, and unique behavior with an apparent happy demeanor that includes frequent laughing, smiling, and excitability. Microcephaly and seizures are also common. Developmental delays are first noted at around age six months; however, the unique clinical features of AS do not become manifest until after age one year. [from GeneReviews]

Prader-Willi syndrome (PWS) is characterized by severe hypotonia and feeding difficulties in early infancy, followed in later infancy or early childhood by excessive eating and gradual development of morbid obesity (unless eating is externally controlled). Motor milestones and language development are delayed. All individuals have some degree of cognitive impairment. A distinctive behavioral phenotype (with temper tantrums, stubbornness, manipulative behavior, and obsessive-compulsive characteristics) is common. Hypogonadism is present in both males and females and manifests as genital hypoplasia, incomplete pubertal development, and, in most, infertility. Short stature is common (if not treated with growth hormone); characteristic facial features, strabismus, and scoliosis are often present. [from GeneReviews]

Turner syndrome is a chromosomal condition that affects development in people who are assigned female at birth. Females typically have two X chromosomes, but in individuals with Turner syndrome, one copy of the X chromosome is missing or altered.\n\nThe most common feature of Turner syndrome is short stature, which becomes evident by about age 5. Reduced functioning of the ovaries, the female reproductive organs that produce egg cells (oocytes) and female sex hormones, is also very common. The ovaries develop normally at first, but egg cells usually die prematurely and most ovarian tissue breaks down before birth. \n\nMany affected individuals do not undergo puberty unless they receive hormone therapy, and most are unable to become pregnant naturally. A small percentage of people with Turner syndrome retain normal ovarian function through young adulthood.\n\nAbout 30 percent of individuals with Turner syndrome have extra folds of skin on the neck (webbed neck), a low hairline at the back of the neck, puffiness or swelling (lymphedema) of the hands and feet, skeletal abnormalities, or kidney problems. One-third to one-half of individuals with Turner syndrome are born with a heart defect, such as a narrowing of the large artery that leaves the heart (coarctation of the aorta) or abnormalities of the valve that connects the aorta to the heart (the aortic valve). Complications associated with these heart defects can be life-threatening.\n\nMost people with Turner syndrome have normal intelligence. Developmental delays, nonverbal learning disabilities, and behavioral problems are possible, although these characteristics vary among affected individuals. [from MedlinePlus Genetics]

48,XXYY syndrome is a chromosomal condition that affects development in people who are assigned male at birth. There is a lot of variability in symptoms between people with 48,XXYY syndrome. Almost all affected individuals have developmental delays in infancy and develop decreased testosterone levels (hypogonadism) during adolescence. People with 48,XXYY syndrome are also at risk for other health problems.\n\n Adolescents and adults with this condition usually have small testes that do not produce enough testosterone, which is the hormone that directs male sexual development. Without treatment, a shortage of testosterone during puberty can lead to reduced facial and body hair, poor muscle development, low energy levels, and an increased risk of breast enlargement (gynecomastia). Because their testes do not function normally, individuals with 48,XXYY syndrome have difficulty having biological children (a condition called infertility), but they may be able to have children using assisted reproductive technologies. \n\n48,XXYY syndrome can affect other parts of the body as well. Affected individuals are often taller than their peers, with an average adult height of 6 feet, 4 inches (193 cm). They may develop a mild to moderate hand tremor that typically starts in adolescence and may increase with age. Dental problems are frequently seen in people with this condition,  including delayed appearance of the primary (baby) or secondary (adult) teeth, thin tooth enamel, crowded or misaligned teeth, and multiple cavities. \n\nAdditionally, individuals with 48,XXYY syndrome may have flat feet (pes planus), elbow abnormalities, abnormal fusion of certain bones in the forearm (radioulnar synostosis), allergies, asthma, type 2 diabetes, seizures, congenital heart defects, and an inflammatory condition in the throat (esophagus) called eosinophilic esophagitis. As people with 48,XXYY get older, they may develop a narrowing of the blood vessels in the legs called peripheral vascular disease. Peripheral vascular disease can cause skin ulcers to form. Affected individuals are also at risk of developing a type of clot called a deep vein thrombosis that occurs in the deep veins of the legs. \n\nMost individuals with 48,XXYY syndrome have an IQ score that ranges from 60 to 80 and have some degree of difficulty with speech and language development. The development of motor skills such as sitting, standing, and walking may be delayed in some children with 48,XXYY syndrome. They may also have poor coordination. Learning disabilities are very common in people with this disorder, especially in the areas of reading and written expression. People with 48,XXYY typically perform better at tasks focused on math, visual-spatial skills such as puzzles, and memorization of locations or directions. Affected individuals have higher-than-average rates of other neurodevelopmental and behavioral disorders, such as attention-deficit/hyperactivity disorder (ADHD); mood disorders, including anxiety and depression; and autism spectrum disorder, which affects communication and social interaction. [from MedlinePlus Genetics]

Phenylalanine hydroxylase (PAH) deficiency results in intolerance to the dietary intake of the essential amino acid phenylalanine and produces a spectrum of disorders. The risk of adverse outcome varies based on the degree of PAH deficiency. Without effective therapy, most individuals with severe PAH deficiency, known as classic PKU, develop profound and irreversible intellectual disability. Affected individuals on an unrestricted diet who have phenylalanine levels above normal but below 1,200 µmol/L (20 mg/dL) are at much lower risk for impaired cognitive development in the absence of treatment. [from GeneReviews]

FMR1 disorders include fragile X syndrome (FXS), fragile X-associated tremor/ataxia syndrome (FXTAS), and fragile X-associated primary ovarian insufficiency (FXPOI). Fragile X syndrome occurs in individuals with an FMR1 full mutation or other loss-of-function variant and is nearly always characterized in affected males by developmental delay and intellectual disability along with a variety of behavioral issues. Autism spectrum disorder is present in 50%-70% of individuals with FXS. Affected males may have characteristic craniofacial features (which become more obvious with age) and medical problems including hypotonia, gastroesophageal reflux, strabismus, seizures, sleep disorders, joint laxity, pes planus, scoliosis, and recurrent otitis media. Adults may have mitral valve prolapse or aortic root dilatation. The physical and behavioral features seen in males with FXS have been reported in females heterozygous for the FMR1 full mutation, but with lower frequency and milder involvement. FXTAS occurs in individuals who have an FMR1 premutation and is characterized by late-onset, progressive cerebellar ataxia and intention tremor followed by cognitive impairment. Psychiatric disorders are common. Age of onset is typically between 60 and 65 years and is more common among males who are hemizygous for the premutation (40%) than among females who are heterozygous for the premutation (16%-20%). FXPOI, defined as hypergonadotropic hypogonadism before age 40 years, has been observed in 20% of women who carry a premutation allele compared to 1% in the general population. [from GeneReviews]

The presence of multiple congenital malformations in a patient. [from NCI]

Chronic myeloid leukemia is a slow-growing cancer of the blood-forming tissue (bone marrow). Normal bone marrow produces red blood cells (erythrocytes) that carry oxygen, white blood cells (leukocytes) that protect the body from infection, and platelets (thrombocytes) that are involved in blood clotting. In chronic myeloid leukemia, the bone marrow produces too many white blood cells. Initially, these cells function relatively normally. However, as the condition progresses, immature white blood cells called myeloblasts (or blasts) accumulate in the blood and bone marrow. The overgrowth of myeloblasts impairs development of other blood cells, leading to a shortage of red blood cells (anemia) and platelets.\n\nChronic myeloid leukemia usually begins after age 60. Common features include excessive tiredness (fatigue), fever, and weight loss. Many affected individuals develop an enlarged spleen (splenomegaly), which can cause a feeling of fullness in the abdomen and a loss of appetite. About half of people with chronic myeloid leukemia do not initially have any signs and symptoms and are diagnosed when a blood test is performed for another reason.\n\nThe condition consists of three phases: the chronic phase, the accelerated phase, and the blast phase (or blast crisis). In the chronic phase, the number of mature white blood cells is elevated, and myeloblasts account for less than 10 percent of blood cells. Signs and symptoms of the condition during this phase are typically mild or absent and worsen slowly. The chronic phase can last from months to years. In the accelerated phase, the number of myeloblasts is slightly higher, making up 10 to 29 percent of blood cells. The signs and symptoms continue to worsen. The accelerated phase usually lasts 4 to 6 months, although it is skipped in some affected individuals. In blast crisis, 30 percent or more of blood or bone marrow cells are myeloblasts. Signs and symptoms are most severe in this phase, including a massively enlarged spleen, bone pain, and weight loss. Serious infections and uncontrolled bleeding can be life-threatening. [from MedlinePlus Genetics]

Acute lymphoblastic leukemia (ALL), also known as acute lymphocytic leukemia, is a subtype of acute leukemia, a cancer of the white blood cells. Somatically acquired mutations in several genes have been identified in ALL lymphoblasts, cells in the early stages of differentiation. Germline variation in certain genes may also predispose to susceptibility to ALL (Trevino et al., 2009). Genetic Heterogeneity of Acute Lymphoblastic Leukemia A susceptibility locus for acute lymphoblastic leukemia (ALL1) has been mapped to chromosome 10q21. See also ALL2 (613067), which has been mapped to chromosome 7p12.2; and ALL3 (615545), which is caused by mutation in the PAX5 gene (167414) on chromosome 9p. [from OMIM]