Achondroplasia (ACH)

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MedlinePlus Genetics: ⁴² Achondroplasia is a form of short-limbed dwarfism. The word achondroplasia literally means "without cartilage formation." Cartilage is a tough but flexible tissue that makes up much of the skeleton during early development. However, in achondroplasia the problem is not in forming cartilage but in converting it to bone (a process called ossification), particularly in the long bones of the arms and legs. Achondroplasia is similar to another skeletal disorder called hypochondroplasia, but the features of achondroplasia tend to be more severe.All people with achondroplasia have short stature. The average height of an adult male with achondroplasia is 131 centimeters (4 feet, 4 inches), and the average height for adult females is 124 centimeters (4 feet, 1 inch). Characteristic features of achondroplasia include an average-size trunk, short arms and legs with particularly short upper arms and thighs, limited range of motion at the elbows, and an enlarged head (macrocephaly) with a prominent forehead. Fingers are typically short and the ring finger and middle finger may diverge, giving the hand a three-pronged (trident) appearance. People with achondroplasia are generally of normal intelligence.Health problems commonly associated with achondroplasia include episodes in which breathing slows or stops for short periods (apnea), obesity, and recurrent ear infections. In childhood, individuals with the condition usually develop a pronounced and permanent sway of the lower back (lordosis) and bowed legs. Some affected people also develop abnormal front-to-back curvature of the spine (kyphosis) and back pain. A potentially serious complication of achondroplasia is spinal stenosis, which is a narrowing of the spinal canal that can pinch (compress) the upper part of the spinal cord. Spinal stenosis is associated with pain, tingling, and weakness in the legs that can cause difficulty with walking. Another uncommon but serious complication of achondroplasia is hydrocephalus, which is a buildup of fluid in the brain in affected children that can lead to increased head size and related brain abnormalities.

MalaCards based summary: Achondroplasia, also known as achondroplastic dwarfism, is related to achondroplasia, severe, with developmental delay and acanthosis nigricans and hypochondroplasia. An important gene associated with Achondroplasia is FGFR3 (Fibroblast Growth Factor Receptor 3), and among its related pathways/superpathways are ERK Signaling and Signal Transduction. The drugs Hormones and Hormone Antagonists have been mentioned in the context of this disorder. Affiliated tissues include long bone, bone and spinal cord, and related phenotypes are bowing of the legs and thoracolumbar kyphosis

GARD: ¹⁹ Achondroplasia is a disorder of bone growth that prevents the changing of cartilage (particularly in the long bones of the arms and legs) to bone. It is characterized by dwarfism, limited range of motion at the elbows, large head size (macrocephaly), small fingers, and normal intelligence. Achondroplasia can cause health complications such as interruption of breathing (apnea), obesity, recurrent ear infections, an exaggerated inward curve of the lumbar spine (lordosis). More serious problems include a narrowing of the spinal canal that can pinch (compress) the upper part of the spinal cord (spinal stenosis) and a buildup of fluid in the brain (hydrocephalus). Some people with Achondroplasia may have delayed motor development early on, but cognition is normal. Achondroplasia is caused by genetic changes in the FGFR3 gene. Inheritance is autosomal dominant.

OMIM®: ⁵⁷ Achondroplasia is the most frequent form of short-limb dwarfism. Affected individuals exhibit short stature caused by rhizomelic shortening of the limbs, characteristic facies with frontal bossing and midface hypoplasia, exaggerated lumbar lordosis, limitation of elbow extension, genu varum, and trident hand (summary by Bellus et al., 1995). (100800) (Updated 08-Dec-2022)

UniProtKB/Swiss-Prot: ⁷³ A frequent form of short-limb dwarfism. It is characterized by a long, narrow trunk, short extremities, particularly in the proximal (rhizomelic) segments, a large head with frontal bossing, hypoplasia of the midface and a trident configuration of the hands. ACH is an autosomal dominant disease.

Orphanet: ⁵⁸ A primary bone dysplasia with micromelia characterized by rhizomelia, exaggerated lumbar lordosis, brachydactyly, and macrocephaly with frontal bossing and midface hypoplasia.

Disease Ontology: ¹¹ An osteochondrodysplasia that results in dwarfism which has material basis in abnormal ossification of cartilage in located in long bone.

Wikipedia: ⁷⁵ Achondroplasia is a genetic disorder with an autosomal dominant pattern of inheritance whose primary... more...

Clinical features from OMIM®:

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