Sack–Barabas syndrome is rare and has an estimated prevalence of 1 in 100,000 to 200,000.

The initial clinical manifestation of vascular problems in patients with SBS is early, about 25% have their first symptoms at age 20 and more than 80% of patients have had at least one complication by the age of 40.

The median survival for one study of SBS patients was only 48 years.

The key for managing Sack–Barabas syndrome is for the patient to be aware of their disease. Close follow up and planning of interventions can significantly prolong and maintain the quality of life of a patient with this disease.

Pregnant affected women must take special care due to the increased risk of premature death due to rupture of arteries, bowel or uterine rupture with a reported mortality rate of 50%.

Genetic counselling is recommended for prospective parents with a family history of Ehlers–Danlos syndrome. Affected parents should be aware of the type of Ehlers-Danlos syndrome they have and its mode of inheritance.

The outlook for individuals with EDS depends on the type of EDS they have. Symptoms vary in severity, even within one sub-type, and the frequency of complications changes individually. Some people have negligible symptoms while others are severely restricted in their daily life. Extreme joint instability, chronic musculoskeletal pain, degenerative joint disease, frequent injuries, and spinal deformities may limit mobility. Severe spinal deformities may affect breathing. In the case of extreme joint instability, dislocations may result from simple tasks such as rolling over in bed or turning a doorknob. Secondary conditions such as autonomic dysfunction or cardiovascular problems, occurring in any type, can affect prognosis and quality of life. Severe mobility-related disability is seen more often in Hypermobility-type than in Classical-type or Vascular-type.

Although all types are potentially life-threatening, the majority of individuals will have a normal lifespan. However, those with blood vessel fragility have a high risk of fatal complications. Arterial rupture is the most common cause of sudden death in EDS. Spontaneous arterial rupture most often occurs in the second or third decade, but can occur at any time. The median life-expectancy in the population with Vascular EDS is 48 years.

Only some variations of Ehlers–Danlos can be positively identified as tied to specific genetic variation.

Mutations in the following genes can cause subtypes of the Ehlers–Danlos syndrome:

- Fibrous proteins: COL1A1, COL1A2, COL3A1, COL5A1, COL5A2, and TNXB

- Enzymes: ADAMTS2, PLOD1, B4GALT7, DSE, and D4ST1/CHST14

Mutations in these genes usually alter the structure, production, or processing of collagen or proteins that interact with collagen. Collagen provides structure and strength to connective tissue. A defect in collagen can weaken connective tissue in the skin, bones, blood vessels, and organs, resulting in the features of the disorder.

Inheritance patterns depend on the type of Ehlers–Danlos syndrome. Most forms of the condition are inherited in an autosomal dominant pattern, which means only one of the two copies of the gene in question must be altered to cause the disorder. The minority are inherited in an autosomal recessive pattern, which means both copies of the gene must be altered for a person to be affected by the condition. It can also be an individual (de novo or "sporadic") mutation. Refer to the summary for each type of Ehlers–Danlos syndrome for a discussion of its inheritance pattern.

The type II and XI collagenopathies are a group of disorders that affect connective tissue, the tissue that supports the body's joints and organs. These disorders are caused by defects in type II or type XI collagen. Collagens are complex molecules that provide structure, strength, and elasticity to connective tissue. Type II and type XI collagen disorders are grouped together because both types of collagen are components of the cartilage found in joints and the spinal column, the inner ear, and the jelly-like substance that fills the eyeball (the vitreous). The type II and XI collagenopathies result in similar clinical features.

Type II tyrosinemia is caused by a deficiency of the enzyme tyrosine aminotransferase (), encoded by the gene "TAT". Tyrosine aminotransferase is the first in a series of five enzymes that converts tyrosine to smaller molecules, which are excreted by the kidneys or used in reactions that produce energy. This form of the disorder can affect the eyes, skin, and mental development. Symptoms often begin in early childhood and include excessive tearing, abnormal sensitivity to light (photophobia), eye pain and redness, and painful skin lesions on the palms and soles. About half of individuals with type II tyrosinemia are also mentally challenged. Type II tyrosinemia occurs in fewer than 1 in 250,000 individuals.

A recent article in 2015 reported a persistent notochord in a fetus at 23 weeks of gestation. The fetus had an abnormal spine, shortened long bones and a left clubfoot. After running postmortem tests and ultrasound, the researchers believed that the fetus suffered from hypochondrogenesis. Hypochondrogenesis is caused when type II collagen is abnormally formed due to a mutation in the COL2A1 gene. Normally, the cartilaginous notochord develops into the bony vertebrae in a human body. The COL2A1 gene results in malformed type II collagen, which is essential in the transition from collagen to bone. This is the first time that researchers found a persistent notochord in a human body due to a COL2A1 mutation.

Tyrosinemia type II (Oculocutaneous tyrosinemia, Richner-Hanhart syndrome) is an autosomal recessive condition with onset between ages 2 and 4 years, when painful circumscribed calluses develop on the pressure points of the palm of the hand and sole of the foot.

Microcephalic osteodysplastic primordial dwarfism type II (MOPD II) is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that MOPD, or a subtype of MOPD, affects less than 200,000 people in the US population and a form of dwarfism associated with brain and skeletal abnormalities.

It was characterized in 1982.

It is associated with "PCNT".

Mutations in the "COL11A1", "COL11A2", and "COL2A1" genes cause collagenopathy, types II and XI. These genes carry instructions for the protein strands that make up type II and type XI collagen. All collagen molecules are made of three protein strands (called alpha chains). The alpha chains may be identical or different, depending on the type of collagen. Type II collagen is made by combining three copies of the alpha chain made by the "COL2A1" gene. Type XI collagen, on the other hand, is composed of three different alpha chains: the products of the "COL2A1", "COL11A1", and "COL11A2" genes.

Mutations in these genes interfere with the proper assembly of type II and XI collagens or reduce the amount of these collagens. Defective or reduced numbers of collagen molecules affect the development of bones and other connective tissues, causing the signs and symptoms of the type II and XI collagenopathies.

Spondyloperipheral dysplasia is an autosomal dominant disorder of bone growth. The condition is characterized by flattened bones of the spine (platyspondyly) and unusually short fingers and toes (brachydactyly). Some affected individuals also have other skeletal abnormalities, short stature, nearsightedness (myopia), hearing loss, and mental retardation. Spondyloperipheral dysplasia is a subtype of collagenopathy, types II and XI.

Collagen, type II, alpha 1 (primary osteoarthritis, spondyloepiphyseal dysplasia, congenital), also known as COL2A1, is a human gene that provides instructions for the production of the pro-alpha1(II) chain of type II collagen.

A 2005 study on rats suggested that hyperprolininemia causes cognitive dysfunction.

Infants with achondrogenesis, type 2 have short arms and legs, a small chest with short ribs, and underdeveloped lungs. Achondrogenesis, type 2 is a subtype of collagenopathy, types II and XI. This condition is also associated with a lack of bone formation (ossification) in the spine and pelvis. Typical 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. The skull bones may be soft, but they often appear normal on X-ray images. In contrast, bones in the spine (vertebrae) and pelvis do not harden.

Achondrogenesis, type 2 and hypochondrogenesis (a similar skeletal disorder) together affect 1 in 40,000 to 60,000 births. Achondrogenesis, type 2 is one of several skeletal disorders caused by mutations in the "COL2A1" gene. This gene provides instructions for making a protein that forms type II collagen. This type of collagen is found mostly in cartilage and in the clear gel that fills the eyeball (the vitreous). It is essential for the normal development of bones and other tissues that form the body's supportive framework (connective tissues). Mutations in the "COL2A1" gene interfere with the assembly of type II collagen molecules, which prevents bones and other connective tissues from developing properly.

Achondrogenesis, type 2 is considered an autosomal dominant disorder because one copy of the altered gene in each cell is sufficient to cause the condition. The disorder is not passed on to the next generation, however, because affected individuals hardly survive past puberty.

This condition is one of a spectrum of skeletal disorders caused by mutations in the "COL2A1" gene. The protein made by this gene forms type II collagen, a molecule found mostly in cartilage and in the clear gel that fills the eyeball (the vitreous). Type II collagen is essential for the normal development of bones and other connective tissues. Mutations in the "COL2A1" gene interfere with the assembly of type II collagen molecules, which prevents bones from developing properly and causes the signs and symptoms of this condition.

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to cause the disorder.

MCAS is a relatively new diagnosis, being unnamed until 2007, and is believed to be very under-diagnosed. New findings are revealing that MCAS is much more prevalent than previously thought.

Joint hypermobility syndrome shares symptoms with other conditions such as Marfan syndrome, Ehlers-Danlos Syndrome, and osteogenesis imperfecta. Experts in connective tissue disorders formally agreed that severe forms of Hypermobility Syndrome and mild forms of Ehlers-Danlos Syndrome Hypermobility Type are the same disorder.[""]

Generalized hypermobility is a common feature in all these hereditary connective tissue disorders and many features overlap, but often features are present that enable differentiating these disorders.

The inheritance pattern of Ehlers-Danlos syndrome varies by type. The arthrochalasia, classic, hypermobility and vascular forms usually have an autosomal dominant pattern of inheritance. Autosomal dominant inheritance occurs when one copy of a gene in each cell is sufficient to cause a disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new (sporadic) gene mutations. Such cases can occur in people with no history of the disorder in their family.

The dermatosparaxis and kyphoscoliosis types of EDS and some cases of the classic and hypermobility forms, are inherited in an autosomal recessive pattern. In autosomal recessive inheritance, two copies of the gene in each cell are altered. Most often, both parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder.

There are no known causes, but the condition appears to be inherited in some patients. Symptoms of MCAS are caused by excessive chemical mediators inappropriately released by mast cells. Mediators include leukotrienes and histamines. The condition may be mild until exacerbated by stressful life events, or symptoms may develop and slowly trend worse with time.

Kniest Dysplasia is an autosomal dominant condition. This means that the person only needs to have one copy of the mutated gene in order to have the condition. People with a family history are at a higher risk of having the disease than people with no family history. A random mutation in the gene can cause a person with no family history to also have the condition.

A congenital disorder of glycosylation (previously called carbohydrate-deficient glycoprotein syndrome) is one of several rare inborn errors of metabolism in which glycosylation of a variety of tissue proteins and/or lipids is deficient or defective. Congenital disorders of glycosylation are sometimes known as CDG syndromes. They often cause serious, sometimes fatal, malfunction of several different organ systems (especially the nervous system, muscles, and intestines) in affected infants. The most common subtype is CDG-Ia (also referred to as PMM2-CDG) where the genetic defect leads to the loss of phosphomannomutase 2, the enzyme responsible for the conversion of mannose-6-phosphate into mannose-1-phosphate.

Arakawa's syndrome II is an autosomal dominant metabolic disorder that causes a deficiency of the enzyme tetrahydrofolate-methyltransferase; affected individuals cannot properly metabolize methylcobalamin, a type of Vitamin B.

It is also called Methionine synthase deficiency, Tetrahydrofolate-methyltransferase deficiency syndrome, and N5-methylhomocysteine transferase deficiency.

No treatment is available for most of these disorders. Mannose supplementation relieves the symptoms in PMI-CDG (CDG-Ib) for the most part, even though the hepatic fibrosis may persist. Fucose supplementation has had a partial effect on some SLC35C1-CDG (CDG-IIc or LAD-II) patients.

Mucolipidosis (ML) is a group of inherited metabolic disorders that affect the body's ability to carry out the normal turnover of various materials within cells.

When originally named, the mucolipidoses derived their name from the similarity in presentation to both mucopolysaccharidoses and sphingolipidoses. A biochemical understanding of these conditions has changed how they are classified. Although four conditions (I, II, III, and IV) have been labeled as mucolipidoses, type I (sialidosis) is now classified as a glycoproteinosis, and type IV (Mucolipidosis type IV) is now classified as a gangliosidosis.

Spondyloepimetaphyseal dysplasia, Strudwick type is an inherited disorder of bone growth that results in dwarfism, characteristic skeletal abnormalities, and problems with vision. The name of the condition indicates that it affects the bones of the spine (spondylo-) and two regions near the ends of bones (epiphyses and metaphyses). This type was named after the first reported patient with the disorder. Spondyloepimetaphyseal dysplasia, Strudwick type is a subtype of collagenopathy, types II and XI.

The signs and symptoms of this condition at birth are very similar to those of spondyloepiphyseal dysplasia congenita, a related skeletal disorder. Beginning in childhood, the two conditions can be distinguished in X-ray images by changes in areas near the ends of bones (metaphyses). These changes are characteristic of spondyloepimetaphyseal dysplasia, Strudwick type.

Spondyloperipheral dysplasia is one of a spectrum of skeletal disorders caused by mutations in the "COL2A1" gene, located on chromosome 12q13.11-q13.2. The protein made by this gene forms type II collagen, a molecule found mostly in cartilage and in the clear gel that fills the vitreous humour (the eyeball). Type II collagen is essential for the normal development of bones and other connective tissues (the tissues that form the body's supportive framework).

Mutations in the "COL2A1" gene interfere with the assembly of type II collagen molecules. The protein made by the altered "COL2A1" gene cannot be used to make type II collagen, resulting in a reduced amount of this type of collagen in the body. Instead of forming collagen molecules, the abnormal protein builds up in cartilage cells (chondrocytes). These changes disrupt the normal development of bones, leading to the signs and symptoms of spondyloperipheral dysplasia.

The disorder is believed to be inherited in an autosomal dominant manner. This indicates that the defective gene responsible for the disorder is located on an autosome (chromosome 12 is an autosome), and only one copy of the defective gene is sufficient to cause the disorder, when inherited from a parent who has the disorder.