Category — Human Genetic Disorders

Achondroplasia is a genetic form of dwarfism due to a problem with bone growth and development. Achondroplasia belongs to a class of dwarfism referred to as a skeletal dysplasia. All skeletal dysplasias are the result of bone growth. Achondroplasia is a common form of dwarfism due to a mutation on one of the first 22 “non-sex” chromosomes. This causes an individual to have a short stature with disproportionately short arms and legs, a large head, and distinctive facial features such as a prominent forehead and flattened midface.

Acid maltase deficiency is a glycogen storage disease and characterized by a buildup of glycogen in the muscles. Glycogen is the chemical substance used by muscles to store sugar and starch. Acid maltase deficiency, also called Pompe disease, is a non-sex linked disorder that is the most serious of the glycogen storage diseases. This is one of many known congenital muscular diseases.

Adrenoleukodystrophy is a progressive condition that affects the adrenal glands and the growth of myelin in the brain and spinal cord. This is an x-linked genetic disorder. It results in the accumulation of long chain fatty acids in the nervous system, adrenal gland, and testes, which disrupts normal activity. There are seven recognized forms of the disease.

The neonatal form appears shortly after birth and includes seizures and delayed neurological development, with death occurring in infancy or young childhood. The cerebral form appears in mid-childhood (at 4-8 years), and the other forms appear during adolescence. One-third of affected people develop neurological symptoms, and about half develop abnormal adrenal function.

As the disease progresses, further signs of damage to the white matter of the brain appear; they include changes in muscle tone, stiffness and contracture deformities, difficulty swallowing, and comma.

Aicardi syndrome is a rare genetic disorder that causes defects of the eyes and brain. Aicardi syndrome is an x-linked dominant condition primarily found in females. Males with the disease die before birth. This is also called Agenesis of Corpus Callosum with Corioretinal Abnormality. It’s called this due to the abnormal formation of the connection between the right and left hemisphere of the brain(corpus callosum), and development of the choroids and retinal sections of the eye.

Alpha-1 Antitrypsin is caused by a deficiency in the protein alpha-1 antitrypsin. This is one of the most common inherited diseases in the Caucasion population. The most common symptom is lung disease. The development of lung disease is also affected by smoking. People with alpha-1 antitrypsin may also develop liver disease and/or liver cancer. The age of onset, rate of progression, and symptoms vary within families.

Androgen insensitivity syndrome is an x-linked recessive disorder. Androgen results from mutations of the gene encoding the androgen receptor. The individuals affected have male chromosomes and male testicles. The external genitals have mild to complete feminization. A woman with androgen insensitivity syndrome has a female appearance and undescended testes, also called testicular feminization.

Apert syndrome is an autosomal dominant disorder. One of the major symptoms is a premature closure of the skull bones leading to facial distortion with an unusually tall skull. Individuals with apert syndrome also suffer from syndactyly, which is the fusion of the fingers and toes. The hand appears mitten-shaped due to the finger infusion.

Ataxia-telangiectasia is a rare genetic neurological disorder that affects various systems in the body. Children don’t show signs of the disease until age one or two. The onset of ataxia is the beginning of progressive degeneration of the part of the brain responsible for movement, the cerebellum. This degeneration leads to a general lack of muscle control and eventually confines the individual to a wheelchair.

Canavan disease is a gene-linked neurological disorder in which the white matter of the brain is degenerated into spongy tissues. This disease is caused by mutations in the enzyme gene called aspartacylase. Canavan is a type of leukodystrophy. Individuals with this disease may suffer from paralysis, blindness, hearing loss, mental retardation, abnormal muscle tone, and an abnormally large head.

Cerebral Palsy is a nonprogressive disorder of movement and posture. This is caused by abnormal development of the motor control centers of the brain. The abnormalities of muscle control are often accompanied by other neurological and physical damage.