Along with the four aspects of the disorder that give it its name, there are also other common symptoms:

- A downward slant of the forehead

- Delayed bone maturation

- Mental retardation

The ocular abnormalities are generally retinal coloboma and nystagmus.

MOMO syndrome is an extremely rare genetic disorder which belongs to the overgrowth syndromes and has been diagnosed in only six cases around the world, and occurs in 1 in 100 million births. The name is an acronym of the four primary aspects of the disorder: Macrosomia (excessive birth weight), Obesity, Macrocephaly (excessive head size) and Ocular abnormalities. It is unknown if it is a life-limiting condition. MOMO syndrome was first diagnosed in 1993 by Professor Célia Priszkulnik Koiffmann, a Brazilian researcher in the Genetic and Clinical Studies of neurodevelopmental disorders.

This syndrome's acronym is an intended pun. It refers to the traditionally tall and obese king of Carnivals, Momus—Rei Momo in Portuguese.

Signs and symptoms of AIP can be variable. Severe and poorly localized abdominal pain is a very common symptom (found in 95% of those affected by AIP). Urinary signs and symptoms such as painful urination, urinary retention, urinary incontinence, or dark urine have also been known to occur. Psychiatric signs and symptoms of AIP may manifest as anxiety, paranoia, irritability, delusions, hallucinations, confusion, and depression. Signs that suggest increased activity of the sympathetic nervous system may be evident including tachycardia, hypertension, palpitations, orthostatic hypotension, sweating, restlessness, and tremor. Other neurologic signs and symptoms of AIP include seizures, peripheral neuropathy, abnormal sensations, chest pain, leg pain, back pain or headache, and coma. Nausea, vomiting, constipation, and diarrhea can also occur. Proximal muscle weakness typically beginning in the arms is characteristic; there can be muscle pain, tingling, numbness, weakness or paralysis; muscle weakness seen in AIP can progress to include the muscles of breathing causing respiratory failure and can be fatal.

AIP patients have an increased risk of developing hepatocellular carcinoma, melanoma, lymphoma, chronic hypertension, chronic kidney disease, and chronic pain.

Acute intermittent porphyria (AIP) is a genetic metabolic disorder affecting the production of heme, the oxygen-binding prosthetic group of hemoglobin. It is characterized by a deficiency of the enzyme porphobilinogen deaminase. Its inheritance is more commonly autosomal dominant; however, autosomal recessive forms of this disorder have occurred. Its incidence is estimated to be between 5 and 10 in 100,000.

King–Kopetzky syndrome is an auditory disability characterised by difficulty in hearing speech in the presence of background noise in conjunction with the finding of normal hearing test results.

It is an example of auditory processing disorder (APD) or "auditory disability with normal hearing (ADN)".

King–Kopetzky syndrome patients have a worse Social Hearing Handicap index (SHHI) than others, indicating they suffer a significant degree of speech-hearing disability.

The condition is named after Samuel J. Kopetzky, who first described the condition in 1948, and P. F. King, who first discussed the aetiological factors behind it in 1954.

It seems that somatic anxiety and situations of stress may be determinants of speech-hearing disability.

Some studies indicated an increased prevalence of a family history of hearing impairment in these patients. The pattern of results is suggestive that King-Kopetzky patients may be related to conditions of autosomal dominant inheritance.

CHS is associated with respiratory arrests during sleep and, in some cases, to neuroblastoma (tumors of the sympathetic ganglia), Hirschsprung disease (partial agenesis of the enteric nervous system), dysphagia (difficulty swallowing) and anomalies of the pupilla. Other symptoms include darkening of skin color from inadequate amounts of oxygen, drowsiness, fatigue, headaches, and an inability to sleep at night. Those suffering from Ondine's curse also have a sensitivity to sedatives and narcotics, which makes respiration even more difficult. A low concentration of oxygen in the red blood cells also may cause hypoxia-induced pulmonary vasoconstriction and pulmonary hypertension, culminating in cor pulmonale or a failure of the right side of the heart. Associated complications may also include gastro-esophageal reflux, ophthalmologic issues, seizures, recurrent pneumonia, developmental delays, learning disabilities and episodes of fainting and temperature disregulation.

Malignant hyperthermia (MH) is a type of severe reaction that occurs to particular medications used during general anesthesia, among those who are susceptible. Symptoms include muscle rigidity, high fever, and a fast heart rate. Complications can include rhabdomyolysis and high blood potassium. Most people who are susceptible are generally otherwise normal when not exposed.

The cause of MH is the use of certain volatile anesthetic agents or succinylcholine in those who are susceptible. Susceptibility can occur due to at least six genetic mutations, with the most common one being of the RYR1 gene. Susceptibility is often inherited from a person's parents in an autosomal dominant manner. The condition may also occur as a new mutation or be associated with a number of inherited muscle diseases, such as central core disease.

In susceptible individuals, the medications induce the release of stored calcium ions within muscle cells. The resulting increase in calcium concentrations within the cells cause the muscle fibers to contract. This generates excessive heat and results in metabolic acidosis. Diagnosis is based on symptoms in the appropriate situation. Family members may be tested to see if they are susceptible by muscle biopsy or genetic testing.

Treatment is with dantrolene and rapid cooling along with other supportive measures. The avoidance of potential triggers is recommended in susceptible people. The condition affects one in 5,000 to 50,000 cases where people are given anesthetic gases. Males are more often affected than females. The risk of death with proper treatment is about 5% while without it is around 75%. While cases that appear similar to MH have been documented since the early 20th century, the condition was only formally recognized in 1960.

Back pain is frequently mentioned as a TMS symptom, but Sarno defines TMS symptoms much more broadly than that:

- "Symptom type:" TMS symptoms include pain, stiffness, weakness, tingling, numbness, muscle contractures, cramps and other negative sensations, according to Sarno.

- "Symptom location:" In addition to the back, Sarno states that TMS symptoms can occur in the neck, knee, arms, wrists, and other parts of the body. Schechter states that the symptoms have a tendency to move to other parts of the body. He considers symptom movement an important indicator that the pain is from TMS.

The typical signs of malignant hyperthermia are due to a hypercatabolic state, which presents as a very high temperature, an increased heart rate and abnormally rapid breathing, increased carbon dioxide production, increased oxygen consumption, mixed acidosis, rigid muscles, and rhabdomyolysis. These signs can develop any time during the administration of the anesthetic triggering agents. It is difficult to find confirmed cases in the postoperative period more than several minutes after discontinuation of anesthetic agents.

Masticatory muscle myositis (MMM) is an inflammatory disease in dogs affecting the muscles of mastication (chewing). It is also known as atrophic myositis or eosinophilic myositis. MMM is the most common inflammatory myopathy in dogs. The disease mainly affects large breed dogs. German Shepherd Dogs and Cavalier King Charles Spaniels may be predisposed. There is a similar disease of the eye muscles found in Golden Retrievers. Symptoms of acute MMM include swelling of the jaw muscles, drooling, and pain on opening the mouth. Ophthalmic signs may include third eyelid protrusion, red eyes, and exophthalmos (protruding eyeballs). In chronic MMM there is atrophy of the jaw muscles, and scarring of the masticatory muscles due to fibrosis may result in inability to open the mouth (trismus). The affected muscles include the temporalis, masseter, and pterygoid muscles. The disease is usually bilateral.

MMM is caused by the presence of 2M fibers in the muscles of the jaw. 2M fibers are not found elsewhere in the body. The immune system recognizes these proteins as foreign to the body and attacks them, resulting in inflammation. Diagnosis of MMM is through either biopsy of the temporalis or masseter muscles or the 2M antibody assay, in which blood serum of the possible MMM-dog is reacted with temporalis tissue of a normal dog, or both. False negatives by the 2M antibody assay may be obtained if MMM is end-stage with destruction of type 2M fibers and marked fibrosis. Treatment is usually with corticosteroids such as prednisone, often with decreasing doses for up to 4–6 months, and in the case of trismus, manual opening of the mouth under anesthesia. Feeding very soft or liquid food during this time is usually necessary. The ultimate degree of recovery of jaw function and muscle mass will depend upon the extent of damage to the muscle tissue. Recurrence of MMM may occur. Misdiagnosis of MMM as a retroorbital abscess based on physical examination and finding of trismus leads to inappropriate treatment with antibiotics, which will not impede the progress of MMM.

Tension myositis syndrome (TMS), also known as tension myoneural syndrome or mindbody syndrome is a name given by John E. Sarno to a condition he describes as characterized by musculoskeletal and nerve symptoms, most notably back pain. Sarno, a Professor of Clinical Rehabilitation Medicine at New York University School of Medicine and Attending Physician at The Rusk Institute of Rehabilitation Medicine at New York University Medical Center, has described TMS in four books, and has stated that the condition may be involved in other pain disorders as well. The treatment protocol for TMS includes education, writing about emotional issues, resumption of a normal lifestyle and, for some patients, support meetings and/or psychotherapy. In 2007, David Schechter (a medical doctor and former student and research assistant of Sarno's) published a peer-reviewed study of TMS treatment showing a 54% success rate for chronic back pain. In terms of statistical significance and success rate, the study outperformed similar studies of other psychological interventions for chronic back pain.

The TMS diagnosis and treatment protocol are not accepted by the mainstream medical community. However, TMS and Sarno's treatment methods have received national attention, including a segment on ABC's "20/20"; an episode of "Larry King Live"; an interview with "Medscape"; and articles in "Newsweek", "The Seattle Times", and "The New York Times". Prominent medical doctors who support TMS treatment include Andrew Weil and Mehmet Oz. Notable patients treated for tension myositis syndrome include Senator Tom Harkin, John Stossel, Howard Stern, and Anne Bancroft.

Sufferers experience pain and swelling in the middle part of the foot and usually limp as a result. Patients that walk with a limp tend to walk with increased weight on the lateral side of the foot. Also, there can be tenderness over the navicular. Patients often complain of pain over the apex.

An X-ray of both feet is used to diagnose disease. The affected foot tends to have a sclerotic and flattened navicular bone.

Central hypoventilation syndrome (CHS) is a respiratory disorder that results in respiratory arrest during sleep. CHS can either be congenital (CCHS) or acquired (ACHS) later in life. It is fatal if untreated. It is also known as Ondine's curse.

ACHS can develop as a result of severe injury or trauma to the brain or brainstem. Congenital cases are very rare and involve a failure of autonomic control of breathing. In 2006, there were only about 200 known cases worldwide. As of 2008, only 1000 total cases were known. The diagnosis may be delayed because of variations in the severity of the manifestations or lack of awareness in the medical community, particularly in milder cases. However, as there have been cases where asymptomatic family members also were found to have CCHS, it may be that these figures only reflect those found to require mechanical ventilation. In all cases, episodes of apnea occur in sleep, but in a few patients, at the most severe end of the spectrum, apnea also occurs while awake.

Although rare, cases of long-term untreated CCHS have been reported and are termed late onset CCHS (LO-CCHS). Cases that go undiagnosed until later life and middle age, although the symptoms are usually obvious in retrospect. There have, however, even been cases of LO-CCHS where family members found to have it have been asymptomatic. Again, lack of awareness in the medical community may cause such a delay. CCHS susceptibility is not known to be affected by gender.

Köhler disease (also spelled "Kohler" and referred to in some texts as Kohler disease I) is a rare bone disorder of the foot found in children between six and nine years of age. The disease typically affects boys, but it can also affect girls. It was first described in 1908 by Alban Köhler (1874–1947), a German radiologist.

It is caused when the navicular bone temporarily loses its blood supply. As a result, tissue in the bone dies and the bone collapses. When treated, it causes no long term problems in most cases although rarely can return in adults. As the navicular bone gets back to normal, symptoms typically abate.

In February 2010, the "Journal of the American Medical Association" reported that the 19-year-old king Tutankhamun may well have died of complications from malaria combined with Köhler disease II.

Convulsive symptoms include painful seizures and spasms, diarrhea, paresthesias, itching, mental effects including mania or psychosis, headaches, nausea and vomiting. Usually the gastrointestinal effects precede central nervous system effects.

Heyde's syndrome is a syndrome of gastrointestinal bleeding from angiodysplasia in the presence of aortic stenosis.

It is named after Edward C. Heyde, MD who first noted the association in 1958. It is caused by the induction of Von Willebrand disease type IIA (vWD-2A) by a depletion of Von Willebrand factor (vWF) in blood flowing through the narrowed valvular stenosis.

Porphyria is a group of diseases in which substances called porphyrins build up, negatively affecting the skin or nervous system. The types that affect the nervous system are also known as acute porphyria, as symptoms are rapid in onset and last a short time. Symptoms of an attack include abdominal pain, chest pain, vomiting, confusion, constipation, fever, high blood pressure, and high heart rate. The attacks usually last for days to weeks. Complications may include paralysis, low blood sodium levels, and seizures. Attacks may be triggered by alcohol, smoking, hormonal changes, fasting, stress, or certain medications. If the skin is affected, blisters or itching may occur with sunlight exposure.

Most types of porphyria are inherited from a person's parents and are due to a mutation in one of the genes that make heme. They may be inherited in an autosomal dominant, autosomal recessive, or X-linked dominant manner. One type, porphyria cutanea tarda, may also be due to increased iron in the liver, hepatitis C, alcohol, or HIV/AIDS. The underlying mechanism results in a decrease in the amount of heme produced and a build-up of substances involved in making heme. Porphyrias may also be classified by whether the liver or the bone marrow is affected. Diagnosis is typically by blood, urine, and stool tests. Genetic testing may be done to determine the specific mutation.

Treatment depends on the type of porphyria and a person's symptoms. The treatment of porphyria of the skin generally involves the avoidance of sunlight. The treatment for acute porphyria may involve giving intravenous heme or a glucose solution. Rarely a liver transplant may be carried out.

The frequency of porphyria is unclear. It is estimated that it affects 1 to 100 per 50,000 people. Rates vary around the world. Porphyria cutanea tarda is believed to be the most common type. The disease was described at least as early as 370 BC by Hippocrates. The underlying mechanism was first described by Felix Hoppe-Seyler in 1871. The name "porphyria" is from the Greek πορφύρα, "porphyra", meaning "purple", a reference to the color of the urine that may occur during an attack.

The dry gangrene is a result of vasoconstriction induced by the ergotamine-ergocristine alkaloids of the fungus. It affects the more poorly vascularized distal structures, such as the fingers and toes. Symptoms include desquamation or peeling, weak peripheral pulses, loss of peripheral sensation, edema and ultimately the death and loss of affected tissues. Vasoconstriction is treated with vasodilators.

The acute porphyrias are acute intermittent porphyria (AIP), variegate porphyria (VP), aminolevulinic acid dehydratase deficiency porphyria (ALAD) and hereditary coproporphyria (HCP). These diseases primarily affect the nervous system, resulting in episodic crises known as acute attacks. The major symptom of an acute attack is abdominal pain, often accompanied by vomiting, hypertension (elevated blood pressure), and tachycardia (an abnormally rapid heart rate). The most severe episodes may involve neurological complications: typically motor neuropathy (severe dysfunction of the peripheral nerves that innervate muscle), which leads to muscle weakness and potentially to quadriplegia (paralysis of all four limbs) and central nervous system symptoms such as seizures and coma. Occasionally, there may be short-lived psychiatric symptoms such as anxiety, confusion, hallucinations, and, very rarely, overt psychosis. All these symptoms resolve once the acute attack passes. Porphyria is not a cause of chronic psychiatric illness, though an association with anxiety and depression has been suggested.

Given the many presentations and the relatively low occurrence of porphyria, patients may initially be suspected to have other, unrelated conditions. For instance, the polyneuropathy of acute porphyria may be mistaken for Guillain–Barré syndrome, and porphyria testing is commonly recommended in those situations.

An individual with this condition is hormonally normal; that is, the person will enter puberty with development of secondary sexual characteristics including thelarche and adrenarche (pubic hair). The person's chromosome constellation will be 46,XX. At least one ovary is intact, if not both, and ovulation usually occurs. Typically, the vagina is shortened and intercourse may, in some cases, be difficult and painful. Medical examination supported by gynecologic ultrasonography demonstrates a complete or partial absence of the cervix, uterus, and vagina.

If there is no uterus, a person with MRKH cannot carry a pregnancy without intervention. It is possible for the person to have genetic offspring by in vitro fertilization (IVF) and surrogacy. Successful uterine transplant has been performed in limited numbers of patients, resulting in several live births, but the technique is not widespread or accessible to many women.

A person with MRKH typically discovers the condition when, during puberty years, the menstrual cycle does not start (primary amenorrhoea). Some find out earlier through surgeries for other conditions, such as a hernia.

The most obvious clinical sign of syringomyelia is pain. Dogs with CM alone do not seem to have signs, but some appear to have facial pain. Common symptoms in human patients include, severe headache and neck pain, dizziness, vertigo, disequilibrium, visual disturbances, ringing in the ears, difficulty swallowing, palpitations, sleep apnea, muscle weakness, impaired fine motor skills, chronic fatigue and painful tingling of the hands and feet, pruritus.

Müllerian agenesis or müllerian aplasia, Mayer–Rokitansky–Küster–Hauser syndrome, or vaginal agenesis is a congenital malformation characterized by a failure of the Müllerian duct to develop, resulting in a missing uterus and variable degrees of vaginal hypoplasia of its upper portion. Müllerian agenesis (including absence of the uterus, cervix and/or vagina) is the cause in 15% of cases of primary amenorrhoea. Because most of the vagina does not develop from the Müllerian duct, instead developing from the urogenital sinus along with the bladder and urethra, it is present even when the Müllerian duct is completely absent.

Because ovaries do not develop from the Müllerian ducts, affected women might have normal secondary sexual characteristics but are infertile due to the lack of a functional uterus. However, motherhood is possible through use of gestational surrogates. Mayer-Rokitansky-Küster-Hauser syndrome (MRKH) is hypothesized to be a result of autosomal dominant inheritance with incomplete penetrance and variable expressivity, which contributes to the complexity involved in identifying of the underlying mechanisms causing the condition. Because of the variance in inheritance, penetrance and expressivity patterns, MRKH is subdivided into two types: type 1, in which only the structures developing from the Müllerian duct are affected (the upper vagina, cervix, and uterus), and type 2, where the same structures are affected, but is characterized by the additional malformations of other body systems most often including the renal and skeletal systems. MRKH type 2 includes MURCS (Müllerian Renal Cervical Somite). The majority of MRKH syndrome cases are characterized as sporadic, but familial cases have provided evidence that, at least for some patients, MRKH is an inherited disorder. The underlying causes of MRKH syndrome is still being investigated, but several causative genes have been studied for their possible association with the syndrome. Most of these studies have served to rule-out genes as causative factors in MRKH, but thus far, only WNT4 has been associated with MRKH with hyperandrogenism.

The medical eponym honors August Franz Josef Karl Mayer (1787–1865), Carl Freiherr von Rokitansky (1804–1878), Hermann Küster (1879–1964), and Georges Andre Hauser (1921–2009).

There are various symptoms of colpocephaly and patients can experience effects ranging from mild to severe. Some patients do not show most of the symptoms related to colpocephaly, such as psychomotor abnormalilities and agenesis of the corpus callosum. In some cases, signs appear later on in life and a significant number of children suffer only from minor disabilities.

The following list includes common symptoms of colpocephaly.

- partial or complete agenesis of the corpus callosum

- intellectual disability

- motor abnormalities

- visual defects such as, crossing of the eyes, missing visual fields, and optic nerve hypoplasia

- spasticity

- seizures

- cerebral palsy

Intracranial abnormalities include:

- Microcephaly

- Agenesis of the corpus callosum

- Meningomyelocele

- Lissencephaly

- Periventricular leukomalacia (PVL)

- Enlargement of the cisterna magna

- Cerebellar hypoplasia

Symptoms include: rigid body, rigid limbs, limbs staying in same position when moved (waxy flexibility), no response, loss of muscle control, and slowing down of bodily functions, such as breathing.