MedlinePlus Genetics:
42
Achondrogenesis is a group of severe disorders that affect cartilage and bone development. These conditions are characterized by a small body, short limbs, and other skeletal abnormalities. As a result of serious health problems, infants with achondrogenesis usually die before birth, are stillborn, or die soon after birth from respiratory failure. However, some infants have lived for a short time with intensive medical support.Researchers have described at least three forms of achondrogenesis, designated as type 1A, type 1B, and type 2. The types are distinguished by their signs and symptoms, inheritance pattern, and genetic cause. However, types 1A and 1B are often hard to tell apart without genetic testing.Achondrogenesis type 1A, which is also called the Houston-Harris type, is the least well understood of the three forms. Affected infants have extremely short limbs, a narrow chest, short ribs that fracture easily, and a lack of normal bone formation (ossification) in the skull, spine, and pelvis.Achondrogenesis type 1B, also known as the Parenti-Fraccaro type, is characterized by extremely short limbs, a narrow chest, and a prominent, rounded abdomen. The fingers and toes are short and the feet may turn inward and upward (clubfeet). Affected infants frequently have a soft out-pouching around the belly-button (an umbilical hernia) or near the groin (an inguinal hernia).Infants with achondrogenesis type 2, which is sometimes called the Langer-Saldino type, have short arms and legs, a narrow chest with short ribs, and underdeveloped lungs. This condition is also associated with a lack of ossification in the spine and pelvis. Distinctive facial features include a prominent forehead, a small chin, and, in some cases, an opening in the roof of the mouth (a cleft palate). The abdomen is enlarged, and affected infants often have a condition called hydrops fetalis, in which excess fluid builds up in the body before birth.
MalaCards based summary:
Achondrogenesis, also known as achondrogenesis syndrome, is related to achondrogenesis, type ia and achondrogenesis, type ib. An important gene associated with Achondrogenesis is COL2A1 (Collagen Type II Alpha 1 Chain), and among its related pathways/superpathways are ERK Signaling and Integrin Pathway. Affiliated tissues include bone, skin and heart, and related phenotypes are macrocephaly and frontal bossing
GARD:
19
Achondrogenesis is a group of severe disorders that are present from birth and affect the development of cartilage and bone. Infants with Achondrogenesis usually have a small body, extremely short arms and legs, other skeletal abnormalities, and underdeveloped lungs. There are at least three forms of Achondrogenesis, type 1A, type 1B and type 2. Achondrogenesis is usually diagnosed during pregnancy by ultrasound and genetic testing is used to distinguish between the three types. Type 1A and 1B Achondrogenesis are both inherited in an autosomal recessive pattern. Type 1A is caused by genetic changes in the TRIP11 gene. Type 1B is caused by genetic changes in the SLC26A2 gene. Type 2 Achondrogenesis is caused by new (de novo) genetic changes in the COL2A1 gene. Because of the severity of this condition, most infants with Achondrogenesis die before or shortly after birth.
Orphanet:
58
A rare group of lethal skeletal dysplasias characterized by an endochondral ossification deficiency that leads to dwarfism with extreme micromelia, a small thorax, a prominent abdomen, anasarca and polyhydramnios. There are three types of achondrogenesis that exist and that differ clinically, radiologically, histologically and genetically: achondrogensis type 1a, type 1b and type 2.
Disease Ontology:
11
An osteochondrodysplasia that has material basis in deficient endochondral ossification which results in dwarfism, short-trunk, short-limbed, anascara, disproportionately large cranium, and a narrow chest which leads to death in utero or during early neonatal period.
Wikipedia:
75
Achondrogenesis is a number of disorders that are the most severe form of congenital chondrodysplasia... more...
Rare bone diseases 
