MedGen

Sickle cell disease (SCD) is characterized by intermittent vaso-occlusive events and chronic hemolytic anemia. Vaso-occlusive events result in tissue ischemia leading to acute and chronic pain as well as organ damage that can affect any organ system, including the bones, spleen, liver, brain, lungs, kidneys, and joints. Dactylitis (pain and/or swelling of the hands or feet) is often the earliest manifestation of SCD. In children, the spleen can become engorged with blood cells in a "splenic sequestration." The spleen is particularly vulnerable to infarction and the majority of individuals with SCD who are not on hydroxyurea or transfusion therapy become functionally asplenic in early childhood, increasing their risk for certain types of bacterial infections, primarily encapsulated organisms. Acute chest syndrome (ACS) is a major cause of mortality in SCD. Chronic hemolysis can result in varying degrees of anemia, jaundice, cholelithiasis, and delayed growth and sexual maturation as well as activating pathways that contribute to the pathophysiology directly. Individuals with the highest rates of hemolysis are at higher risk for pulmonary artery hypertension, priapism, and leg ulcers and may be relatively protected from vaso-occlusive pain. [from GeneReviews]

The term "galactosemia" refers to disorders of galactose metabolism that include classic galactosemia, clinical variant galactosemia, and biochemical variant galactosemia (not covered in this chapter). This GeneReview focuses on: Classic galactosemia, which can result in life-threatening complications including feeding problems, failure to thrive, hepatocellular damage, bleeding, and E coli sepsis in untreated infants. If a lactose-restricted diet is provided during the first ten days of life, the neonatal signs usually quickly resolve and the complications of liver failure, sepsis, and neonatal death are prevented; however, despite adequate treatment from an early age, children with classic galactosemia remain at increased risk for developmental delays, speech problems (termed childhood apraxia of speech and dysarthria), and abnormalities of motor function. Almost all females with classic galactosemia manifest hypergonadatropic hypogonadism or premature ovarian insufficiency (POI). Clinical variant galactosemia, which can result in life-threatening complications including feeding problems, failure to thrive, hepatocellular damage including cirrhosis, and bleeding in untreated infants. This is exemplified by the disease that occurs in African Americans and native Africans in South Africa. Persons with clinical variant galactosemia may be missed with newborn screening as the hypergalactosemia is not as marked as in classic galactosemia and breath testing is normal. If a lactose-restricted diet is provided during the first ten days of life, the severe acute neonatal complications are usually prevented. African Americans with clinical variant galactosemia and adequate early treatment do not appear to be at risk for long-term complications, including POI. [from GeneReviews]

Hemoglobin H disease is a subtype of alpha-thalassemia (see 604131) in which patients have compound heterozygosity for alpha(+)-thalassemia, caused by deletion of one alpha-globin gene, and for alpha(0)-thalassemia, caused by deletion in cis of 2 alpha-globin genes (summary by Lal et al., 2011). When 3 alpha-globin genes become inactive because of deletions with or without concomitant nondeletional mutations, the affected individual has only 1 functional alpha-globin gene. These people usually have moderate anemia and marked microcytosis and hypochromia. In affected adults, there is an excess of beta-globin chains within erythrocytes that will form beta-4 tetramers, also known as hemoglobin H (summary by Chui et al., 2003). Hb H disease is usually caused by the combination of alpha(0)-thalassemia with deletional alpha(+)-thalassemia, a combination referred to as 'deletional' Hb H disease. In a smaller proportion of patients, Hb H disease is caused by an alpha(0)-thalassemia plus an alpha(+)-thalassemia point mutation or small insertion/deletion. Such a situation is labeled 'nondeletional' Hb H disease. Patients with nondeletional Hb H disease are usually more anemic, more symptomatic, more prone to have significant hepatosplenomegaly, and more likely to require transfusions (summary by Lal et al., 2011). [from OMIM]

Wilson disease is a disorder of copper metabolism that can present with hepatic, neurologic, or psychiatric disturbances, or a combination of these, in individuals ranging from age three years to older than 50 years; symptoms vary among and within families. Liver disease includes recurrent jaundice, simple acute self-limited hepatitis-like illness, autoimmune-type hepatitis, fulminant hepatic failure, or chronic liver disease. Neurologic presentations include movement disorders (tremors, poor coordination, loss of fine-motor control, chorea, choreoathetosis) or rigid dystonia (mask-like facies, rigidity, gait disturbance, pseudobulbar involvement). Psychiatric disturbance includes depression, neurotic behaviors, disorganization of personality, and, occasionally, intellectual deterioration. Kayser-Fleischer rings, frequently present, result from copper deposition in Descemet's membrane of the cornea and reflect a high degree of copper storage in the body. [from GeneReviews]

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by production of autoantibodies against nuclear, cytoplasmic, and cell surface molecules that transcend organ-specific boundaries. Tissue deposition of antibodies or immune complexes induces inflammation and subsequent injury of multiple organs and finally results in clinical manifestations of SLE, including glomerulonephritis, dermatitis, thrombosis, vasculitis, seizures, and arthritis. Evidence strongly suggests the involvement of genetic components in SLE susceptibility (summary by Oishi et al., 2008). Genetic Heterogeneity of Systemic Lupus Erythematosus An autosomal recessive form of systemic lupus erythematosus (SLEB16; 614420) is caused by mutation in the DNASE1L3 gene (602244) on chromosome 3p14.3. An X-linked dominant form of SLE (SLEB17; 301080) is caused by heterozygous mutation in the TLR7 gene (300365) on chromosome Xp22. See MAPPING and MOLECULAR GENETICS sections for a discussion of genetic heterogeneity of susceptibility to SLE. [from OMIM]

Glycogen storage disease VII is an autosomal recessive metabolic disorder characterized clinically by exercise intolerance, muscle cramping, exertional myopathy, and compensated hemolysis. Myoglobinuria may also occur. The deficiency of the muscle isoform of PFK results in a total and partial loss of muscle and red cell PFK activity, respectively. Raben and Sherman (1995) noted that not all patients with GSD VII seek medical care because in some cases it is a relatively mild disorder. [from OMIM]

Erythropoietic protoporphyria (EPP) is characterized by cutaneous photosensitivity (usually beginning in infancy or childhood) that results in tingling, burning, pain, and itching within 30 minutes after exposure to sun or ultraviolet light and may be accompanied by swelling and redness. Symptoms (which may seem out of proportion to the visible skin lesions) may persist for hours or days after the initial phototoxic reaction. Photosensitivity remains for life. Multiple episodes of acute photosensitivity may lead to chronic changes of sun-exposed skin (lichenification, leathery pseudovesicles, grooving around the lips) and loss of lunulae of the nails. Approximately 20%-30% of individuals with EPP have some degree of liver dysfunction, which is typically mild with slight elevations of the liver enzymes. Up to 5% may develop more advanced liver disease which may be accompanied by motor neuropathy similar to that seen in the acute porphyrias. [from GeneReviews]

X-linked hyper IgM syndrome (HIGM1), a disorder of abnormal T- and B-cell function, is characterized by low serum concentrations of IgG, IgA, and IgE with normal or elevated serum concentrations of IgM. Mitogen proliferation may be normal, but NK- and T-cell cytotoxicity can be impaired. Antigen-specific responses are usually decreased or absent. Total numbers of B cells are normal but there is a marked reduction of class-switched memory B cells. Defective oxidative burst of both neutrophils and macrophages has been reported. The range of clinical findings varies, even within the same family. More than 50% of males with HIGM1 develop symptoms by age one year, and more than 90% are symptomatic by age four years. HIGM1 usually presents in infancy with recurrent upper- and lower-respiratory tract bacterial infections, opportunistic infections including Pneumocystis jirovecii pneumonia, and recurrent or protracted diarrhea that can be infectious or noninfectious and is associated with failure to thrive. Neutropenia is common; thrombocytopenia and anemia are less commonly seen. Autoimmune and/or inflammatory disorders (such as sclerosing cholangitis) as well as increased risk for neoplasms have been reported as medical complications of this disorder. Significant neurologic complications, often the result of a CNS infection, are seen in 5%-15% of affected males. Liver disease, a serious complication of HIGM1 once observed in more than 80% of affected males by age 20 years, may be decreasing with adequate screening and treatment of Cryptosporidium infection. [from GeneReviews]

Congenital erythropoietic porphyria (CEP) is characterized in most individuals by severe cutaneous photosensitivity with blistering and increased friability of the skin over light-exposed areas. Onset in most affected individuals occurs at birth or early infancy. The first manifestation is often pink-to-dark red discoloration of the urine. Hemolytic anemia is common and can range from mild to severe, with some affected individuals requiring chronic blood transfusions. Porphyrin deposition may lead to corneal ulcers and scarring, reddish-brown discoloration of the teeth (erythrodontia), and bone loss and/or expansion of the bone marrow. The phenotypic spectrum, however, is broad and ranges from nonimmune hydrops fetalis in utero to late-onset disease with only mild cutaneous manifestations in adulthood. [from GeneReviews]

The spectrum of COL4A1-related disorders includes: small-vessel brain disease of varying severity including porencephaly, variably associated with eye defects (retinal arterial tortuosity, Axenfeld-Rieger anomaly, cataract) and systemic findings (kidney involvement, muscle cramps, cerebral aneurysms, Raynaud phenomenon, cardiac arrhythmia, and hemolytic anemia). On imaging studies, small-vessel brain disease is manifest as diffuse periventricular leukoencephalopathy, lacunar infarcts, microhemorrhage, dilated perivascular spaces, and deep intracerebral hemorrhages. Clinically, small-vessel brain disease manifests as infantile hemiparesis, seizures, single or recurrent hemorrhagic stroke, ischemic stroke, and isolated migraine with aura. Porencephaly (fluid-filled cavities in the brain detected by CT or MRI) is typically manifest as infantile hemiparesis, seizures, and intellectual disability; however, on occasion it can be an incidental finding. HANAC (hereditary angiopathy with nephropathy, aneurysms, and muscle cramps) syndrome usually associates asymptomatic small-vessel brain disease, cerebral large vessel involvement (i.e., aneurysms), and systemic findings involving the kidney, muscle, and small vessels of the eye. Two additional phenotypes include isolated retinal artery tortuosity and nonsyndromic autosomal dominant congenital cataract. [from GeneReviews]

Any hereditary spherocytosis in which the cause of the disease is a mutation in the ANK1 gene. [from MONDO]

The phenotypic spectrum of glucose transporter type 1 deficiency syndrome (Glut1 DS) is now known to be a continuum that includes the classic phenotype as well as paroxysmal exercise-induced dyskinesia and epilepsy (previously known as dystonia 18 [DYT18]) and paroxysmal choreoathetosis with spasticity (previously known as dystonia 9 [DYT9]), atypical childhood absence epilepsy, myoclonic astatic epilepsy, and paroxysmal non-epileptic findings including intermittent ataxia, choreoathetosis, dystonia, and alternating hemiplegia. The classic phenotype is characterized by infantile-onset seizures, delayed neurologic development, acquired microcephaly, and complex movement disorders. Seizures in classic early-onset Glut1 DS begin before age six months. Several seizure types occur: generalized tonic or clonic, focal, myoclonic, atypical absence, atonic, and unclassified. In some infants, apneic episodes and abnormal episodic eye-head movements similar to opsoclonus may precede the onset of seizures. The frequency, severity, and type of seizures vary among affected individuals and are not related to disease severity. Cognitive impairment, ranging from learning disabilities to severe intellectual disability, is typical. The complex movement disorder, characterized by ataxia, dystonia, and chorea, may occur in any combination and may be continuous, paroxysmal, or continual with fluctuations in severity influenced by environmental factors such as fasting or with infectious stress. Symptoms often improve substantially when a ketogenic diet is started. [from GeneReviews]

Most characteristically, Aicardi-Goutières syndrome (AGS) manifests as an early-onset encephalopathy that usually, but not always, results in severe intellectual and physical disability. A subgroup of infants with AGS present at birth with abnormal neurologic findings, hepatosplenomegaly, elevated liver enzymes, and thrombocytopenia, a picture highly suggestive of congenital infection. Otherwise, most affected infants present at variable times after the first few weeks of life, frequently after a period of apparently normal development. Typically, they demonstrate the subacute onset of a severe encephalopathy characterized by extreme irritability, intermittent sterile pyrexias, loss of skills, and slowing of head growth. Over time, as many as 40% develop chilblain skin lesions on the fingers, toes, and ears. It is becoming apparent that atypical, sometimes milder, cases of AGS exist, and thus the true extent of the phenotype associated with pathogenic variants in the AGS-related genes is not yet known. [from GeneReviews]

People with the mild form may have very mild anemia or sometimes have no symptoms. People with the moderate form typically have anemia, jaundice, and splenomegaly. Many also develop gallstones. The signs and symptoms of moderate hereditary spherocytosis usually appear in childhood. Individuals with the moderate/severe form have all the features of the moderate form but also have severe anemia. Those with the severe form have life-threatening anemia that requires frequent blood transfusions to replenish their red blood cell supply. They also have severe splenomegaly, jaundice, and a high risk for developing gallstones. Some individuals with the severe form have short stature, delayed sexual development, and skeletal abnormalities.

There are four forms of hereditary spherocytosis, which are distinguished by the severity of signs and symptoms. They are known as the mild form, the moderate form, the moderate/severe form, and the severe form. It is estimated that 20 to 30 percent of people with hereditary spherocytosis have the mild form, 60 to 70 percent have the moderate form, 10 percent have the moderate/severe form, and 3 to 5 percent have the severe form.

Hereditary spherocytosis is a condition that affects red blood cells. People with this condition typically experience a shortage of red blood cells (anemia), yellowing of the eyes and skin (jaundice), and an enlarged spleen (splenomegaly). Most newborns with hereditary spherocytosis have severe anemia, although it improves after the first year of life. Splenomegaly can occur anytime from early childhood to adulthood. About half of affected individuals develop hard deposits in the gallbladder called gallstones, which typically occur from late childhood to mid-adulthood. [from MedlinePlus Genetics]

Phosphoglycerate kinase-1 deficiency is an X-linked recessive condition with a highly variable clinical phenotype that includes hemolytic anemia, myopathy, and neurologic involvement. Patients can express 1, 2, or all 3 of these manifestations (Shirakawa et al., 2006). [from OMIM]

Elliptocytosis is a hematologic disorder characterized by elliptically shaped erythrocytes and a variable degree of hemolytic anemia. Usually inherited as an autosomal dominant trait, elliptocytosis results from mutation in any one of several genes encoding proteins of the red cell membrane skeleton (summary by McGuire et al., 1988). Genetic Heterogeneity of Elliptocytosis Elliptocytosis-2 (130600) is caused by mutation in the SPTA1 gene (182860). Elliptocytosis-3 (617948) is caused by mutation in the SPTB gene (182870). Elliptocytosis-4 (166900), also known as Southeast Asian ovalocytosis, is caused by mutation in the SLC4A1 gene (109270). Also see pyropoikilocytosis (266140). See Delaunay (2007) for a discussion of the molecular basis of hereditary red cell membrane disorders. [from OMIM]

C3 glomerulopathy (C3G) is a complex ultra-rare complement-mediated renal disease caused by uncontrolled activation of the complement alternative pathway (AP) in the fluid phase (as opposed to cell surface) that is rarely inherited in a simple mendelian fashion. C3G affects individuals of all ages, with a median age at diagnosis of 23 years. Individuals with C3G typically present with hematuria, proteinuria, hematuria and proteinuria, acute nephritic syndrome or nephrotic syndrome, and low levels of the complement component C3. Spontaneous remission of C3G is uncommon, and about half of affected individuals develop end-stage renal disease (ESRD) within ten years of diagnosis, occasionally developing the late comorbidity of impaired visual acuity. [from GeneReviews]

RAS-associated leukoproliferative disorder is characterized by lymphadenopathy, splenomegaly, and variable autoimmune phenomena, including autoimmune hemolytic anemia, idiopathic thrombocytopenic purpura, and neutropenia. Laboratory studies show an expansion of lymphocytes due to defective apoptosis, as well as significant autoantibodies. Some patients have recurrent infections, and there may be an increased risk of hematologic malignancy (summary by Oliveira, 2013 and Niemela et al., 2010). The disorder shows significant overlap with autoimmune lymphoproliferative syndrome (ALPS; 601859) and was originally designated ALPS IV. [from OMIM]

GATA1-related cytopenia is characterized by thrombocytopenia and/or anemia ranging from mild to severe. One or more of the following may also be present: platelet dysfunction, mild ß-thalassemia, neutropenia, and congenital erythropoietic porphyria (CEP) in males. Thrombocytopenia typically presents in infancy as a bleeding disorder with easy bruising and mucosal bleeding (e.g., epistaxis). Anemia ranges from minimal (mild dyserythropoiesis) to severe (hydrops fetalis requiring in utero transfusion). At the extreme end of the clinical spectrum, severe hemorrhage and/or erythrocyte transfusion dependence are life long; at the milder end, anemia and the risk for bleeding may decrease spontaneously with age. Heterozygous females may have mild-to-moderate symptoms such as menorrhagia. [from GeneReviews]

EPB42-related hereditary spherocytosis (EPB42-HS) is a chronic nonimmune hemolytic anemia that is usually of mild-to-moderate severity. EPB42-HS can present with jaundice as early as the first 24 hours of life or can present later in childhood with anemia resulting from a hemolytic crisis or aplastic crisis (usually associated with a viral infection). In addition to the hematologic manifestations, serious complications include splenomegaly, which can become evident in early childhood, and cholelithiasis, which usually becomes evident in the second or third decade of life. Typical laboratory findings in EPB42-HS include anemia (decreased hemoglobin [Hgb] level) and reticulocytosis (increased percentage of reticulocytes), with high mean corpuscular Hgb concentration, presence of spherocytes in the peripheral blood smear, significantly decreased or absent haptoglobin, mildly increased osmotic fragility in osmotic fragility assay, increased Omin (osmolality at which 50% of red blood cells hemolyze), and decreased maximal elongation index (EImax) in osmotic gradient ektacytometry. [from GeneReviews]