Because MOMO is such a rare disorder, very few studies have been conducted into its causes. Current research suggests that it is linked to a de novo (new) autosomal dominant mutation.

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.

Urine and serum show raised levels of porphobilinogen.

Assay the red blood cells for the level of porphobilinogen deaminase.

The main candidates for testing are those with a close relative who has suffered an episode of MH or have been shown to be susceptible. The standard procedure is the "caffeine-halothane contracture test", CHCT. A muscle biopsy is carried out at an approved research center, under local anesthesia. The fresh biopsy is bathed in solutions containing caffeine or halothane and observed for contraction; under good conditions, the sensitivity is 97% and the specificity 78%. Negative biopsies are "not" definitive, so any patient who is suspected of MH by their medical history or that of blood relatives is generally treated with non-triggering anesthetics, even if the biopsy was negative. Some researchers advocate the use of the "calcium-induced calcium release" test in addition to the CHCT to make the test more specific.

Less invasive diagnostic techniques have been proposed. Intramuscular injection of halothane 6 vol% has been shown to result in higher than normal increases in local among patients with known malignant hyperthermia susceptibility. The sensitivity was 100% and specificity was 75%. For patients at similar risk to those in this study, this leads to a positive predictive value of 80% and negative predictive value of 100%. This method may provide a suitable alternative to more invasive techniques.

A 2002 study examined another possible metabolic test. In this test, intramuscular injection of caffeine was followed by local measurement of the ; those with known MH susceptibility had a significantly higher (63 versus 44 mmHg). The authors propose larger studies to assess the test's suitability for determining MH risk.

Genetic testing is being performed in a limited fashion to determine susceptibility to MH. In people with a family history of MH, analysis for "RYR1" mutations may be useful.

Diagnosis is made on the basis of history and a high index of suspicion. On examination there is tenderness to palpation on navicular head. Radiographs reveal typical changes of increased density and narrowing of the navicular bone

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.

Treatment usually involves resting the affected foot, taking pain relievers and trying to avoid putting pressure on the foot. In acute cases, the patient is often fitted with a cast that stops below the knee. The cast is usually worn for 6 to 8 weeks. After the cast is taken off, some patients are prescribed arch support for about 6 months. Also, moderate exercise is often beneficial, and physical therapy may help as well.

Prognosis for children with this disease is very good. It may persist for some time, but most cases are resolved within two years of the initial diagnosis. Although in most cases no permanent damage is done, some will have lasting damage to the foot. Also, later in life, Kohler's disease can spread to the hips.

If drugs have caused the attack, discontinuing the offending substances is essential. A high-carbohydrate (10% glucose) infusion is recommended, which may aid in recovery.

Hematin and heme arginate is the treatment of choice during an acute attack. Heme is not a curative treatment, but can shorten attacks and reduce the intensity of an attack. Side-effects are rare but can be serious. Pain is extremely severe and almost always requires the use of opiates to reduce it to tolerable levels. Pain should be treated as early as medically possible due to its severity.

Nausea can be severe; it may respond to phenothiazine drugs but is sometimes intractable. Hot water baths or showers may lessen nausea temporarily, but can present a risk of burns or falls.

Seizures often accompany this disease. Most seizure medications exacerbate this condition. Treatment can be problematic: Barbiturates and Primidone must be avoided as they commonly precipitate symptoms. Some benzodiazepines are safe, and, when used in conjunction with newer anti-seizure medications such as gabapentin, offer a possible regimen for seizure control.

Diagnosis is made primarily through physical assessment of the skin, family history of Mongolian spots, and subjective data given by the care giver. No tests are currently available for diagnosing Mongolian spots.

Below is a list of criteria for diagnosing TMS, according to Schechter and Sarno:

- "Lack of known physical cause:" Schechter and Sarno state that a physical examination, tests and imaging studies is needed to rule out serious conditions, such as tumors. Sarno considers spinal disc herniations to generally be harmless, because he says the symptom location does not even correlate to the herniation location.

- "Tender points:" While medical doctors use eleven of eighteen tender points as a diagnostic criteria for fibromyalgia, Sarno states that he uses six main tender points to diagnose TMS: two tender points in the upper trapezius muscles, two in the lumbar paraspinal muscles and two in the lateral upper buttocks. He states that these are found in 99% of TMS patients.

- "History of other psychosomatic disorders:" Schechter and Sarno consider a prior history of other psychosomatic disorders an indication that the patient may have TMS. They list irritable bowel syndrome and tension headache as examples of psychosomatic disorders.

Schechter and Sarno state that if a patient is unable to visit a medical doctor who is trained in TMS, then the patient should see a traditional medical doctor to rule out serious disorders, such as fractures, tumors and infections.

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.

Heyde's syndrome is now known to be gastrointestinal bleeding from angiodysplasic lesions due to acquired vWD-2A deficiency secondary to aortic stenosis, and the diagnosis is made by confirming the presence of those three things. Gastrointestinal bleeding may present as bloody vomit, dark, tarry stool from metabolized blood, or fresh blood in the stool. In a person presenting with these symptoms, endoscopy, gastroscopy, and/or colonoscopy should be performed to confirm the presence of angiodysplasia. Aortic stenosis can be diagnosed by auscultation for characteristic heart sounds, particularly a crescendo-decrescendo (i.e., 'ejection') murmur, followed by echocardiography to measure aortic valve area (see diagnosis of aortic stenosis). While Heyde's syndrome may exist alone with no other symptoms of aortic stenosis, the person could also present with evidence of heart failure, fainting, or chest pain. Finally, Heyde's syndrome can be confirmed using blood tests for vWD-2A, although traditional blood tests for von Willebrand factor may result in false negatives due to the subtlety of the abnormality. The gold standard for diagnosis is gel electrophoresis; in people with vWD-2A, the large molecular weight von Willebrand factors will be absent from the SDS-agarose electrophoresis plate.

People generally require tracheostomy and lifetime mechanical ventilation on a ventilator in order to survive. However, it has now been shown that biphasic cuirass ventilation can effectively be used without the need for a tracheotomy. Other potential treatments for Ondine's curse include oxygen therapy and medicine for stimulating the respiratory system. Currently, problems arise with the extended use of ventilators, including fatal infections and pneumonia.

Most people with CCHS (unless they have the Late Onset form) do not survive infancy, unless they receive ventilatory assistance during sleep. An alternative to a mechanical ventilator is diaphragm pacing.

Children with CCHS develop life-threatening episodes of apnea with cyanosis, usually in the first months of life. Medical evaluation excludes lesions of the brain, heart, and lungs but demonstrates impaired responses to build-up of carbon dioxide (hypercapnia) and decreases of oxygen in the circulation (hypoxia), the two strongest stimuli to increase breathing rate.

Polysomnography shows that hypoventilation is most marked during slow-wave sleep. In the most severe cases, hypoventilation is present during other nonrapid eye movement sleep stages and even wakefulness. A subset of CCHS patients are at very high risk for developing malignant neural crest-derived tumors, such as neuroblastoma.

The sequence of "PHOX2B" reveals mutations in 91% of the cases.

As in many disorders that are very rare, an infant with this unusual form of sleep apnea suffers from the probability that their physician has most likely never seen another case and will not recognize the diagnosis. In some locations, such as France, optimal management of patients, once identified, has been aided by the creation of a national registry and the formation of a network of centers.

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.

Further diagnostic tests of affected organs may be required, such as nerve conduction studies for neuropathy or an ultrasound of the liver. Basic biochemical tests may assist in identifying liver disease, hepatocellular carcinoma, and other organ problems.

Whole spine MR imaging may be used to evaluate the extent of syrinx formation (fluid filled cavity within the spinal cord) in CM dogs, developing a thermal camera-based screening test for the disorder and a method of measuring the actual syrinx volume from MR images.

Before the introduction of MRI, the diagnosis of CM and SM were commonly confused with that of allergic skin disorders, disk disease, ear infections and epilepsy. After CM was reported in human patients, the initial research was provided for the diagnosis of animals. MRI in animals is safe, however, to ensure that the patient remains motionless, light general anesthesia is required.

According to recent studies, thermography may be a useful tool in the diagnosis of CM and SM. Thermography requires no sedation or clipping of hair for a dog to be imaged by the infrared camera. After the image is captured, computer software is used to assess changes in the temperature and color pattern to detect abnormality.

Mongolian spots usually resolve by early childhood and hence no treatment is generally needed if they are located in the sacral area. However, sometimes it may be required for extra sacral lesions to have surgical correction. Q-switched alexandrite lasers have been used for treatment. Good results are obtained if treatment is initiated before the age of 20 years. In a study done by the University of Tokyo, the effectiveness of the Q-switched alexandrite laser in treating Mongolian spots was evaluated. A retrospective study was done from April 2003 to September 2011. 16 patients, aged 14-55, were treated with Q-switched alexandrite laser. A good therapeutic outcome was achieved on the whole group, however two patients with sacral Mongolian spots suffered from inflammatory hyperpigmentation, and two patients got post inflammatory hypopigmentation after seven sessions of laser treatment.

Porphyria is diagnosed through biochemical analysis of blood, urine, and stool. In general, urine estimation of porphobilinogen (PBG) is the first step if acute porphyria is suspected. As a result of feedback, the decreased production of heme leads to increased production of precursors, PBG being one of the first substances in the porphyrin synthesis pathway. In nearly all cases of acute porphyria syndromes, urinary PBG is markedly elevated except for the very rare ALA dehydratase deficiency or in patients with symptoms due to hereditary tyrosinemia type I. In cases of

mercury- or arsenic poisoning-induced porphyria, other changes in porphyrin profiles appear, most notably elevations of uroporphyrins I & III, coproporphyrins I & III, and pre-coproporphyrin.

Repeat testing during an attack and subsequent attacks may be necessary in order to detect a porphyria, as levels may be normal or near-normal between attacks. The urine screening test has been known to fail in the initial stages of a severe, life-threatening attack of acute intermittent porphyria.

Up to 90% of the genetic carriers of the more common, dominantly inherited acute hepatic porphyrias (acute intermittent porphyria, hereditary coproporphyria, variegate porphyria) have been noted in DNA tests to be latent for classic symptoms and may require DNA or enzyme testing. The exception to this may be latent post-puberty genetic carriers of hereditary coproporphyria.

As most porphyrias are rare conditions, general hospital labs typically do not have the expertise, technology, or staff time to perform porphyria testing. In general, testing involves sending samples of blood, stool, and urine to a reference laboratory. All samples to detect porphyrins must be handled properly. Samples should be taken during an acute attack; otherwise a false negative result may occur. Samples must be protected from light and either refrigerated or preserved.

If all the porphyrin studies are negative, one must consider pseudoporphyria. A careful medication review often will find the cause of pseudoporphyria.

A number of treatments have become available to create a functioning vagina, yet in the absence of a uterus currently no surgery is available to make pregnancy possible. Standard approaches use vaginal dilators and/or surgery to develop a functioning vagina to allow for penetrative sexual intercourse. A number of surgical approaches have been used. In the McIndoe procedure, a skin graft is applied to form an artificial vagina. After the surgery, dilators are still necessary to prevent vaginal stenosis. The Vecchietti procedure has been shown to result in a vagina that is comparable to a normal vagina in patients. In the Vecchietti procedure, a small plastic “olive” is threaded against the vaginal area, and the threads are drawn through the vaginal skin, up through the abdomen and through the navel using laparoscopic surgery. There the threads are attached to a traction device. The operation takes about 45 minutes. The traction device is then tightened daily so the olive is pulled inwards and stretches the vagina by approximately 1 cm per day, creating a vagina approximately 7 cm deep in 7 days, although it can be more than this. Another approach is the use of an autotransplant of a resected sigmoid colon using laparoscopic surgery; results are reported to be very good with the transplant becoming a functional vagina.

Uterine transplantation has been performed in a number of people with MRKH, but the surgery is still in the experimental stage. Since ovaries are present, people with this condition can have genetic children through IVF with embryo transfer to a gestational carrier. Some also choose to adopt. In October 2014 it was reported that a month earlier a 36-year-old Swedish woman became the first person with a transplanted uterus to give birth to a healthy baby. She was born without a uterus, but had functioning ovaries. She and the father went through IVF to produce 11 embryos, which were then frozen. Doctors at the University of Gothenburg then performed the uterus transplant, the donor being a 61-year-old family friend. One of the frozen embryos was implanted a year after the transplant, and the baby boy was born prematurely at 31 weeks after the mother developed pre-eclampsia.

Promising research include the use of laboratory-grown structures, which are less subject to the complications of non-vaginal tissue, and may be grown using the person's own cells as a culture source. The recent development of engineered vaginas using the patient's own cells has resulted in fully functioning vaginas capable of menstruation and orgasm in a number of patients showing promise of fully correcting this condition in some of the sufferers.

The type of treatment needed for dogs diagnosed with CM/SM depends on the severity of the condition and the age of the dog. Young dogs with clinical signs should be considered for surgical removal to minimize the progression of the disease as the dog ages. Older dogs with little or no clinical signs may be treated medically, rather than surgically. However, severe cases of CM/SM may require surgery regardless of age. The goal of surgery is syrynx decompression through restoration of normal cerebrospinal fluid circulation.

The surgical treatment of CM in dogs is described as "foramen magnum decompression FMD". Despite an approximately 80% success rate with this surgical technique, there is a 25% to 50% relapse, primarily due to excessive scar tissue formation at the decompression site. A cranioplasty may be performed instead, in which a plate, constructed using titanium mesh and bone cement, is fixed to the back of the skull following a standard FMD procedure. The procedure had been effective in humans. The postoperative relapse rate associated with the titanium cranioplasty procedure is less than 7%.

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.

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 definitive treatment for Heyde's syndrome is surgical replacement of the aortic valve. Recently, it has been proposed that transcatheter aortic valve implantation (TAVI) can also be used for definitive management. Direct surgical treatment of the bleeding (e.g. surgical resection of the bleeding portion of the bowel) is only rarely effective.

Medical management of symptoms is possible also, although by necessity temporary, as definitive surgical management is required to bring levels of von Willebrand factor back to normal. In severe bleeding, blood transfusions and IV fluid infusions can be used to maintain blood pressure. In addition, desmopressin (DDAVP) is known to be effective in people with von Willebrand's disease, including people with valvular heart disease. Desmopressin stimulates release of von Willebrand factor from blood vessel endothelial cells by acting on the V2 receptor, which leads to decreased breakdown of Factor VIII. Desmopressin is thus sometimes used directly to treat mild to moderate acquired von Willebrand's disease and is an effective prophylactic agent for the reduction of bleeding during heart valve replacement surgery.