Macrocephaly is a condition in which circumference of the human head is abnormally large. It may be pathological or harmless, and can be a familial genetic characteristic. People diagnosed with macrocephaly will receive further medical tests to determine whether the syndrome is accompanied by particular disorders. Those with benign or familial macrocephaly are considered to have megalencephaly.
Weissenbacher–Zweymuller syndrome (WZS), also called Pierre-Robin syndrome with fetal chondrodysplasia, is an autosomal recessive congenital disorder, linked to mutations in the COL11A2 gene, which codes for the α2 strand of collagen type XI. It is a collagenopathy, types II and XI disorder. The condition was first characterized in 1964 by G. Weissenbacher and Ernst Zweymüller.
Mucopolysaccharidoses are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal enzymes needed to break down molecules called glycosaminoglycans (GAGs). These long chains of sugar carbohydrates occur within the cells that help build bone, cartilage, tendons, corneas, skin and connective tissue. GAGs are also found in the fluids that lubricate joints.
Lysosomal storage diseases are a group of over 70 rare inherited metabolic disorders that result from defects in lysosomal function. Lysosomes are sacs of enzymes within cells that digest large molecules and pass the fragments on to other parts of the cell for recycling. This process requires several critical enzymes. If one of these enzymes is defective due to a mutation, the large molecules accumulate within the cell, eventually killing it.
Sanfilippo syndrome, also known as mucopolysaccharidosis type III (MPS III), is a rare lifelong genetic disease that mainly affects the brain and spinal cord. It is caused by a problem with how the body breaks down certain large sugar molecules called glycosaminoglycans (also known as GAGs or mucopolysaccharides). In children with this condition, these sugar molecules build up in the body and eventually lead to damage of the central nervous system and other organ systems.
Hurler syndrome, also known as mucopolysaccharidosis Type IH (MPS-IH), Hurler's disease, and formerly gargoylism, is a genetic disorder that results in the buildup of large sugar molecules called glycosaminoglycans (GAGs) in lysosomes. The inability to break down these molecules results in a wide variety of symptoms caused by damage to several different organ systems, including but not limited to the nervous system, skeletal system, eyes, and heart.
Cystinosis is a lysosomal storage disease characterized by the abnormal accumulation of cystine, the oxidized dimer of the amino acid cysteine. It is a genetic disorder that follows an autosomal recessive inheritance pattern. It is a rare autosomal recessive disorder resulting from accumulation of free cystine in lysosomes, eventually leading to intracellular crystal formation throughout the body. Cystinosis is the most common cause of Fanconi syndrome in the pediatric age group. Fanconi syndrome occurs when the function of cells in renal tubules is impaired, leading to abnormal amounts of carbohydrates and amino acids in the urine, excessive urination, and low blood levels of potassium and phosphates.
Glycogen storage disease type IV (GSD IV), or Andersen's Disease, is a form of glycogen storage disease, which is caused by an inborn error of metabolism. It is the result of a mutation in the GBE1 gene, which causes a defect in the glycogen branching enzyme. Therefore, glycogen is not made properly and abnormal glycogen molecules accumulate in cells; most severely in cardiac and muscle cells. The severity of this disease varies on the amount of enzyme produced. GSD IV is autosomal recessive, which means each parent has a mutant copy of the gene, but show no symptoms of the disease. Having an autosomal recessive inheritance pattern, males and females are equally likely to be affected by Andersen's disease. Classic Andersen's disease typically becomes apparent during the first few months after the patient is born. Approximately 1 in 20,000 to 25,000 newborns have a glycogen storage disease. Andersen's disease affects 1 in 800,000 individuals worldwide, with 3% of all GSDs being type IV. The disease was described and studied first by Dorothy Hansine Andersen.
Heřmanský–Pudlák syndrome is an extremely rare autosomal recessive disorder which results in oculocutaneous albinism, bleeding problems due to a platelet abnormality, and storage of an abnormal fat-protein compound. It is thought to affect around 1 in 500,000 people worldwide, with a significantly higher occurrence in Puerto Ricans, with a prevalence of 1 in 1800. Many of the clinical research studies on the disease have been conducted in Puerto Rico.
Hunter syndrome, or mucopolysaccharidosis type II, is a rare genetic disorder in which large sugar molecules called glycosaminoglycans build up in body tissues. It is a form of lysosomal storage disease. Hunter syndrome is caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (I2S). The lack of this enzyme causes heparan sulfate and dermatan sulfate to accumulate in all body tissues. Hunter syndrome is the only MPS syndrome to exhibit X-linked recessive inheritance.
The GM1 gangliosidoses, usually shortened to GM1, are gangliosidoses caused by mutation in the GLB1 gene resulting in a deficiency of beta-galactosidase. The deficiency causes abnormal storage of acidic lipid materials in cells of the central and peripheral nervous systems, but particularly in the nerve cells, resulting in progressive neurodegeneration. GM1 is a rare lysosomal storage disorder with a prevalence of 1 to every 100,000 to 200,000 live births worldwide, although rates are higher in some regions.
An osteochondrodysplasia, or skeletal dysplasia, is a disorder of the development of bone and cartilage. Osteochondrodysplasias are rare diseases. About 1 in 5,000 babies are born with some type of skeletal dysplasia. Nonetheless, if taken collectively, genetic skeletal dysplasias or osteochondrodysplasias comprise a recognizable group of genetically determined disorders with generalized skeletal affection. These disorders lead to disproportionate short stature and bone abnormalities, particularly in the arms, legs, and spine. Skeletal dysplasia can result in marked functional limitation and even mortality.
Maroteaux–Lamy syndrome, or Mucopolysaccharidosis Type VI (MPS-VI), is an inherited disease caused by a deficiency in the enzyme arylsulfatase B (ARSB). ASRB is responsible for the breakdown of large sugar molecules called glycosaminoglycans. In particular, ARSB breaks down dermatan sulfate and chondroitin sulfate. Because people with MPS-VI lack the ability to break down these GAGs, these chemicals build up in the lysosomes of cells. MPS-VI is therefore a type of lysosomal storage disease.
Metaphyseal dysplasia, or Pyle disease, is a disorder of the bones. It is a rare disease in which the outer part of the shafts of long bones is thinner than normal and there is an increased chance of fractures. Its hallmark feature is an abnormality of the long bones in the arms and legs in which the ends (metaphyses) of the bones are abnormally broad; the shape of the bones resembles a boat oar or paddle. The broad metaphyses are due to enlargement of the spongy inner layer of bone. Although trabecular bone is expanded, the dense outermost layer of bone is thinner than normal. As a result, the bones are fragile and fracture easily. The bone abnormalities in the legs commonly cause knock knees in affected individuals.
Rabson–Mendenhall syndrome is a rare autosomal recessive disorder characterized by severe insulin resistance. The disorder is caused by mutations in the insulin receptor gene. Symptoms include growth abnormalities of the head, face and nails, along with the development of acanthosis nigricans. Treatment involves controlling blood glucose levels by using insulin and incorporating a strategically planned, controlled diet. Also, direct actions against other symptoms may be taken This syndrome usually affects children and has a prognosis of 1–2 years.
N-acetylgalactosamine-6-sulfatase is an enzyme that, in humans, is encoded by the GALNS gene.
Scheie syndrome is a disease caused by a deficiency in the enzyme iduronidase, leading to the buildup of glycosaminoglycans (GAGs) in the body. It is the most mild subtype of mucopolysaccharidosis type I; the most severe subtype of this disease is called Hurler Syndrome.
Antley–Bixler syndrome is a rare, severe autosomal recessive congenital disorder characterized by malformations and deformities affecting the majority of the skeleton and other areas of the body.
Coarse facial features is a constellation of facial features that are present in many inborn errors of metabolism.
Mucopolysaccharidosis type I is a spectrum of diseases in the mucopolysaccharidosis family. It results in the buildup of glycosaminoglycans due to a deficiency of alpha-L iduronidase, an enzyme responsible for the degradation of GAGs in lysosomes. Without this enzyme, a buildup of dermatan sulfate and heparan sulfate occurs in the body.
