Pachyosteosclerosis is a combination of thickening (pachyostosis) and densification (osteosclerosis) of bones. It makes bones more heavy, but also more fragile. The condition often occurs in aquatic vertebrates, especially those living in shallow waters, creating ballast as an adaptation for maintaining neutral buoyancy and horizontal trim. It is in no way pathological. To resist roll, it frequently is found especially in ventral bones, whereas concentration near the lungs helps in maintaining trim.

Examples of animals showing pachyosteosclerosis are seacows (dugongs and manatees), the extinct Plesiosauria and Mesosauria and extinct aquatic sloths.

Spinal osteoarthropathy (Charcot's Disease) is a rare disease affecting reptiles (including snakes and lizards) which causes abnormal bone growth on vertebrae, giving the reptile a lumpy appearance. The growth of animals with this disease is limited (a python may only grow long), and their life spans are greatly shortened.

The movement of reptiles with this ailment appears jittery and wooden, and the head movement will be greatly restricted. The condition worsens as the patient ages; the end result is a reptile fused together by its own bones. They are usually euthanized well before this stage, but in general these animals can live their short lives comfortably with little pain.

Spinal osteoarthropathy can also occur in humans.

It can result from syphilis, yaws, Paget's disease of bone, Vitamin D deficiency, or Weismann-Netter-Stuhl syndrome.

It can be due to osteomalacia

Quite often, the presenting symptom of ornithine aminotransferase (OAT) deficiency is myopia which progresses to night blindness. The onset of myopia is often in early childhood. Ophthalmological findings in affected individuals include constricted visual fields, posterior subcapsular cataracts (can begin in late teens), elevated dark adaptation thresholds and decreased or absent electroretinographic responses. Symptoms of OAT deficiency are progressive, and between the ages of 45 and 65, most affected individuals are almost completely blind.

In some cases, affected individuals will present in the neonatal period with disease that closely mimics a classic urea cycle defect, such as ornithine transcarbamylase deficiency, as the block in ornithine metabolism leads to secondary dysfunction of the urea cycle. These individuals present with hyperammonemia, poor feeding, failure to thrive and increased excretion of orotic acid.

Saber refers to the tibia's resemblance to the curve of a saber sword.

Reticular pigmented anomaly of the flexures (also known as "dark dot disease", and "Dowling–Degos' disease") is a fibrous anomaly of the flexures or bending parts of the axillae, neck and inframammary/sternal areas. It is an autosomal-dominant pigmentary disorder that may appear in adolescence or adulthood. This condition is due to mutations in structural/desmosomal proteins found within stratified squamous epithelium.

Dark dot disease is associated with "KRT5".

Laminopathies and other nuclear envelopathies have a large variety of clinical symptoms including skeletal and/or cardiac muscular dystrophy, lipodystrophy and diabetes, dysplasia, dermo- or neuropathy, leukodystrophy, and progeria (premature aging). Most of these symptoms develop after birth, typically during childhood or adolescence. Some laminopathies however may lead to an early death, and mutations of lamin B (LMNB1 gene) may be lethal before or at birth.

The following are clear signs of Kyphoscoliosis:

- Abnormal hunch along with a presence of S or C-like shape.

- Uneven lengths of arms and legs

- Presence of associated disorders likes hypertension, neurological disorders

- Abnormal gait

Laminopathies ("" + "") are a group of rare genetic disorders caused by mutations in genes encoding proteins of the nuclear lamina. They are included in the more generic term "nuclear envelopathies" that was coined in 2000 for diseases associated with defects of the nuclear envelope. Since the first reports of laminopathies in the late 1990s, increased research efforts have started to uncover the vital role of nuclear envelope proteins in cell and tissue integrity in animals.

Scheuermann's disease is considered to be a form of juvenile osteochondrosis of the spine. It is found mostly in teenagers and presents a significantly worse deformity than postural kyphosis. Patients suffering with Scheuermann’s kyphosis cannot consciously correct their posture. The apex of their curve, located in the thoracic vertebrae, is quite rigid.

Scheuermann's disease is notorious for causing lower and mid-level back and neck pain, which can be severe and disabling. The sufferer may feel pain at the apex of the curve, which is aggravated by physical activity and by periods of standing or sitting; this can have a significantly detrimental effect to their lives as their level of activity is curbed by their disability. The sufferer may feel isolated or uneasy amongst their peers if they are children, depending on the level of deformity.

In addition to the pain associated with Scheuermann's disease, many sufferers of the disorder have loss of vertebral height, and depending on where the apex of the curve is, may have a visual 'hunchback' or 'roundback'. It has been reported that curves in the lower thoracic region cause more pain, whereas curves in the upper region present a more visual deformity. Nevertheless, it is typically pain or cosmetic reasons that prompt sufferers to seek help for their condition. In studies, kyphosis is better characterized for the thoracic spine than for the lumbar spine.

The seventh and tenth thoracic vertebrae are most commonly affected. It causes backache and spinal curvature. In very serious cases it may cause internal problems and spinal cord damage, but these cases are extremely rare. The curvature of the back decreases height, thus putting pressure on internal organs, wearing them out more quickly than the natural aging process; surgical procedures are almost always recommended in this case.

Kyphosis by itself refers to an excessive convex curvature of spine occurring in the thoracic and sacral regions. A normal thoracic curvature from the 1st to the 12th spine has a naturally occurring convex shape with angles ranging from 20 degrees to 45 degrees. When the curvature goes past 45 degrees, the condition is termed as Kyphosis.

Kyphosis, depending on the extent of curvature can result in many discomforts including breathing and digestion difficulties, cardiovascular issues, and even neurological deformities. The greater the extent of deformity, the more pressing the need becomes for a surgery.

Kyphosis by itself is of several types, including postural kyphosis caused by slouching. Such forms of kyphosis can be reversed to a certain extent by correcting muscular imbalances. The more debilitating version of kyphosis is Scheuermann’s kyphosis, found mostly in teenagers. There are few other causes of Kyphosis as well, such as congenital, nutritional or osteoporosis induced and post-traumatic.

Depending on the type of Kyphosis, the extent of curvature, the age of the patient, various treatment modalities can be suggested including the provision for posture correction, braces, physiotherapy for correcting the muscular imbalance, and finally the surgery. Surgery can be most useful in patients who have an extensive deformity. The rate of post-surgery complications may be higher in elderly patients.

Ornithine aminotransferase deficiency (also known as gyrate atrophy of the choroid and retina) is an inborn error of ornithine metabolism, caused by decreased activity of the enzyme ornithine aminotransferase. Biochemically, it can be detected by elevated levels of ornithine in the blood. Clinically, it presents initially with poor night vision, which slowly progresses to total blindness. It is believed to be inherited in an autosomal recessive manner. Approximately 200 known cases have been reported in the literature. The incidence is highest in Finland, estimated at 1:50,000.

Research suggests there can be some adverse effect on muscles and also the brain. The cause of this is somewhat unclear but may relate to very low levels of creatine often found in this population.

Tratement may include vitamin B6, Lysine or dramatic dietary change to minimise Arginine from patients diet. Research has indicated that these treatments may be somewhat effective in lowering ornathine blood concerntration levels in some patients, either in combination or individually. Vitamin B6 has been found to be very effective in a small proportion of patients.

Physical examination findings in patients with CDGP are essentially normal, with the exception of immature appearance for age. Body proportions may reflect the delay in growth. During childhood, the upper-to-lower body ratio may be greater than normal, reflecting more infantile proportions. In adults, the ratio is often reduced (i.e., <1 in whites, <0.9 in blacks) as a result of the longer period of leg (long bone) growth.

Symptoms associated with scoliosis can include:

- Pain in back, shoulders, and neck and buttock pain nearest bottom of the back

- Respiratory and/or cardiac problems in severe cases

- Constipation due to curvature causing "tightening" of stomach, intestines, etc.

- Limited mobility secondary to pain or functional limitation in adults

- Painful menstruation

The signs of scoliosis can include:

- Uneven musculature on one side of the spine

- Rib prominence or a prominent shoulder blade, caused by rotation of the rib cage in thoracic scoliosis

- Uneven hips, arms or leg lengths

- Slow nerve action

- Heart and lung problems in severe cases

- Calcium deposits in the cartilage endplate and sometimes in the disc itself

Patients with black bone disease are asymptomatic as children or young adults, but their urine may turn brown or even inky black if collected and left exposed to open air. Pigmentation may be noted in the cartilage of the ear as well as other cartilage, and the sclera and corneal limbus of the eye.

After the age of thirty people begin to develop pain in the weight-bearing joints of the spine, hips and knees. The pain can be severe to the point that interferes with activities of daily living and may affect ability to work. Joint replacement surgery (hip and shoulder) is often necessary at a relatively young age. In the longer term, the involvement of the spinal joints leads to reduced movement of the rib cage and can affect breathing. Bone mineral density may be affected, increasing the risk of bone fractures, and rupture of tendons and muscles may occur.

Valvular heart disease, mainly calcification and regurgitation of the aortic and mitral valves, may occur, and in severe and progressive cases valve replacement may be necessary. Irregularities in the heart rhythm and heart failure affect a significant proportion of people with alkaptonuria (40% and 10% respectively). Hearing loss affects 40% of people. There is also a propensity to developing kidney stones, and eventually also gallstones and stones in the prostate and salivary glands (sialolithiasis).

Spinal osteoarthropathy is genetic, carried by parents and passed onto their offspring. Another known cause of this disease is a vitamin B12 deficiency in the reptile, which can be treated by injecting its food with a vitamin supplement.

Gibbus deformity is a form of structural kyphosis typically found in the upper lumbar and lower thoracic vertebrae, where one or more adjacent vertebrae become wedged. Gibbus deformity most often develops in young children as a result of spinal tuberculosis and is the result of collapse of vertebral bodies. This can in turn lead to spinal cord compression causing paraplegia.

In addition to tuberculosis, other possible causes of gibbus deformity include pathological diseases, hereditary and congenital conditions, and physical trauma to the spine that results in injury. Gibbus deformity may result from the sail vertebrae associated with cretinism (the childhood form of hypothyroidism), mucopolysaccharidosis (MPS), and certain congenital syndromes, including achondroplasia. Because most children with MPS I (Hurler Syndrome) also exhibit symptoms of a gibbus deformity, the latter can possibly be used to identify the former.

Gibbus deformity is included in a subset of structural kyphosis that is distinguished by a higher-degree angle in the spinal curve that is specific to these forms of kyphosis. Other conditions within this subset include Pott’s disease and Scheuermann kyphosis, but gibbus deformity is marked by an especially sharp angle. Viewed from behind, the resulting hunchback is more easily seen when bending forward. A kyphosis of >70° can be an indication of the need for surgery and these surgeries can be necessary for children as young as two years old, with a reported average of 8 years of age.

Pycnodysostosis causes the bones to be abnormally dense (osteopetrosis); the last bones of the fingers (the distal phalanges) to be unusually short; and delays the normal closure of the connections (sutures) of the skull bones in infancy, so that the "soft spot" (fontanelle) on top of the head remains widely open.

Those with the syndrome have brittle bones which easily break, especially in the legs and feet. The jaw and collar bone (clavicle) are also particularly prone to fractures.

Other abnormalities involve the head and face, teeth, collar bones, skin, and nails. The front and back of the head are prominent. Within the open sutures of the skull, there may be many small bones (called wormian bones). The midface is less full than usual. The nose is prominent. The jaw can be small. The palate is narrow and grooved. The baby teeth are late coming in and may be lost much later than usual. The permanent teeth can also be slow to appear. The permanent teeth are commonly irregular and teeth may be missing (hypodontia). The collar bones are often underdeveloped and malformed. The skin over the back of the fingers is very wrinkled. The nails are flat and grooved.

Pycnodysostosis also causes problems that may become evident with time. Aside from the broken bones, the distal phalanges and the collar bone can undergo slow progressive deterioration. Vertebral defects may permit the spine to curve laterally resulting in scoliosis. The dental problems often require orthodontic care and cavities are common.

There are several kinds of kyphosis (ICD-10 codes are provided):

- Postural kyphosis (M40.0), the most common type, normally attributed to slouching, can occur in both the old and the young. In the young, it can be called "slouching" and is reversible by correcting muscular imbalances. In the old, it may be a case of hyperkyphosis and called "dowager's hump". About one third of the most severe hyperkyphosis cases in older people have vertebral fractures. Otherwise, the aging body does tend towards a loss of musculoskeletal integrity, and hyperkyphosis can develop due to aging alone.

- Scheuermann's kyphosis (M42.0) is significantly worse cosmetically and can cause varying degrees of pain, and can also affect different areas of the spine (the most common being the midthoracic area). Scheuermann's kyphosis is considered a form of juvenile osteochondrosis of the spine, and is more commonly called Scheuermann's disease. It is found mostly in teenagers and presents a significantly worse deformity than postural kyphosis. A patient suffering from Scheuermann’s kyphosis cannot consciously correct posture. The apex of the curve, located in the thoracic vertebrae, is quite rigid. The patient may feel pain at this apex, which can be aggravated by physical activity and by long periods of standing or sitting. This can have a significantly detrimental effect on their lives, as their level of activity is curbed by their condition; they may feel isolated or uneasy amongst peers if they are children, depending on the level of deformity. Whereas in postural kyphosis, the vertebrae and discs appear normal, in Scheuermann’s kyphosis, they are irregular, often herniated, and wedge-shaped over at least three adjacent levels. Fatigue is a very common symptom, most likely because of the intense muscle work that has to be put into standing or sitting properly. The condition appears to run in families. Most patients who undergo surgery to correct their kyphosis have Scheuermann's disease.

- Congenital kyphosis (Q76.4) can result in infants whose spinal column has not developed correctly in the womb. Vertebrae may be malformed or fused together and can cause further progressive kyphosis as the child develops. Surgical treatment may be necessary at a very early stage and can help maintain a normal curve in coordination with consistent follow-ups to monitor changes. However, the decision to carry out the procedure can be very difficult due to the potential risks to the child. A congenital kyphosis can also suddenly appear in teenage years, more commonly in children with cerebral palsy and other neurological disorders.

- Nutritional kyphosis can result from nutritional deficiencies, especially during childhood, such as vitamin D deficiency (producing rickets), which softens bones and results in curving of the spine and limbs under the child's body weight.

- Gibbus deformity is a form of structural kyphosis, often a "sequela" to tuberculosis.

- Post-traumatic kyphosis (M84.0) can arise from untreated or ineffectively treated vertebral fractures.

Dilaceration is a developmental disturbance in shape of teeth. It refers to an angulation, or a sharp bend or curve, in the root or crown of a formed tooth.

Melanism is a development of the dark-colored pigment melanin in the skin or its appendages and is the opposite of albinism. The word "melanism" is derived from the ("black pigment").

Pseudo-melanism, also called abundism, is another variant of pigmentation, characterized by dark spots or enlarged stripes, which cover a large part of the body of the animal, making it appear melanistic.

A deficiency in or total absence of melanin pigments is called amelanism.

The morbid deposition of black matter, often of a malignant character causing pigmented tumors, is called melanosis. For a description of melanin-related disorders, see melanin and ocular melanosis.

Children with constitutional delay of growth and puberty (CDGP), the most common cause of short stature and pubertal delay in males, typically have slowed linear growth within the first 3 years of life. In this variant of normal growth, linear growth velocity and weight gain slows beginning as young as age 3–6 months, resulting in downward crossing of growth percentiles, which often continues until age 2–3 years. At that time, growth resumes at a normal rate, and these children grow either along the lower growth percentiles or beneath the curve but parallel to it for the remainder of the prepubertal years.

At the expected time of puberty, the height of children with CDGP begins to drift further from the growth curve because of delay in the onset of the pubertal growth spurt. Catch-up growth, onset of puberty, and pubertal growth spurt occur later than average, resulting in normal adult stature and sexual development. Although CDGP is a variant of normal growth rather than a disorder, delays in growth and sexual development may contribute to psychological difficulties, warranting treatment for some individuals. Recent studies have suggested that referral bias is largely responsible for the impression that normal short stature per se is a cause of psycho-social problems; non-referred children with short stature do not differ from those with more normal stature in school performance or socialization.

The condition is thought to be due to trauma or possibly a delay in tooth eruption relative to bone remodeling gradients during the period in which tooth is forming. The result is that the position of the calcified portion of the tooth is changed and the remainder of the tooth is formed at an angle.

The curve or bend may occur anywhere along the length of the tooth, sometimes at the cervical portion, at other times midway along the root or even just at the apex of the root, depending upon the amount of root formed when the injury occurred.

Such an injury to a permanent tooth, resulting in dilaceration, often follows traumatic injury to the deciduous predecessor in which that tooth is driven apically into the jaw.

Osteosclerosis is a disorder that is characterized by abnormal hardening of bone and an elevation in bone density. It may predominantly affect the medullary portion and/or cortex of bone. Plain radiographs are a valuable tool for detecting and classifying osteosclerotic disorders. It can manifest in localized or generalized osteosclerosis. Localized osteosclerosis can be caused by Legg–Calvé–Perthes disease, sickle-cell disease and osteoarthritis among others. Osteosclerosis can be classified in accordance with the causative factor into acquired and hereditary.

The presentation of Ullrich congenital muscular dystrophy in an affected individual is as follows:

- Muscle weakness

- Difficulty walking

- Contractures (neck)

- Joint looseness