Understanding the Uncommon: Rare Diseases

There is no single, widely accepted definition for rare diseases. Some definitions are solely based on the number of people living with a disease in a population while others consider factors such as the existence of adequate treatments or the severity of the disease. The definitions used in medical literature and by national health plans are similarly divided, with criteria ranging from 1/1,000 to 1/200,000. The following are some of these rare diseases:

CHARGE Syndrome
CHARGE syndrome is a result of abnormalities in parts of the genetic makeup of a child, usually before birth. It causes a range of physical and health problems that vary from child to child. The syndrome is named after the clinical features of the disease which are: C for coloboma (basically anomalies in the eyes), H for heart defects, A for atresia choanae (narrowing of the nasal cavity), R for retardation of growth/development, G for genital abnormalities and E for ear malformation.

Due to the wide range of findings in children with CHARGE syndrome, the diagnosis can be hard to make. Every individual with it is unique, therefore to identify the symptoms, a few general signs can be observed:

  • Weakness or paralysis of the facial muscles (facial palsy)
  • Difficulty swallowing, which causes feeding problems
  • Outer ear malformations like floppy ears or small or absent earlobes

There can also be behavioral signs like repetitive behaviour, sensation-seeking (eg. seeking bright colours or strongly flavoured food and difficulty shifting attention from one thing to another).
Genetic testing is also recommended to confirm a CHARGE syndrome diagnosis. Treatment for the syndrome may include surgery and therapy, but all should be done with early intervention. Note that it is not something hereditary but rather a spontaneous change in the genetics of a fetus.

Necrobiosis Lipoidica
Necrobiosis lipoidica is a rare disease of the degeneration of collagen in the skin. It is traditionally associated with type 1 diabetes mellitus and also results in the formation of ulcers. The disease causes the thickening of the walls of the blood vessels, deposition of fat and also damages to the skin which usually increase in size and number.

There is no known cause of Necrobiosis but recent studies are suggestive that it is caused by damage to the smallest blood vessels in the body’s vital organs. It is even suggested that just 0.3% – 1.2% of those with diabetes mellitus develop the disease over time. It is also possible to not have diabetes and still have the disease.

Necrobiosis lipoidica simply precedes diabetes in up to 14% of cases, appears simultaneously in up to 24%, and occurs after diabetes is diagnosed in 62% of cases but there is no proven connection between the diabetes itself and the possibility of developing necrobiosis lipoidica.

Although no treatment has proven to be effective in necrobiosis lipoidica, compression therapy can be used to control edema and help promote healing in patients with associated venous and lymphatic abnormalities.

Sheehan’s Syndrome
This syndrome occurs due to massive postpartum hemorrhage and is also referred to as pituitary ischaemic necrosis. It results in injury to the pituitary gland following extreme blood loss during childbirth. This severe blood loss deprives the pituitary gland of the oxygen it needs to work properly and as a result, causes the death of some of the tissue in gland, and because the pituitary gland is also the ‘master gland’ it also affects other glands and hormone secretion.

The symptoms of this disease are infrequent or no menses, excessive fatigue, lactation failure, weight loss, excessive tiredness, reduction in libido, loss of hair, cold intolerance, fainting spells and low blood pressure.

Its treatment involves taking hormones for the rest of the patient’s life to replace the ones that their body is no longer making and prevention entails avoiding pregnancy complications that can lead to severe blood loss. Sheehan’s syndrome is still rarely seen and diagnosed late as the symptoms are mostly non-specific although postpartum haemorrhage is quite common. A total of two clinical cases are seen in Nigeria per year.

Harlequin Ichthyosis
Ichthyosis is a family of genetic skin disorders, characterized by dry, thickened, scaly skin with severe morbidity and inclination to mortality. Ichthyosis is a group of related genetic conditions that impact how the body makes and sheds skin cells. Harlequin ichthyosis is the most severe kind of ichthyosis that one can have, and it is usually life-long. It is given the name Harlequin due to the facial appearance and the triangular and diamond-shaped pattern of the scaly skin. It is caused by the mutation of a gene responsible for making a protein that is essential for the normal development of skin cells.

The Harlequin foetus may have poorly developed or absent ears, inflexible arms, feet, and digits which may also be underdeveloped, a severely compromised skin barrier leading to excessive water loss, electrolyte abnormalities, temperature dysregulation, and an increased risk of life-threatening infection. The tight, armorlike scales can also restrict respiration and result in poor feeding and impaired intestinal absorption.

Treatment includes placement in high-humidity incubators and proper nutrition. Nurses can also apply moisturizers to the babies’ skin and a drug called etretinate may be given to help remove the thick, plate-like scales covering the skin. After these scales peel off, babies may be able to go home.

Complications due to the lost skin barrier can set in very early therefore intensive supportive and care from a multi-disciplinary team is required for effective management of the disease. This extremely rare condition is found in just 1 in 300,000 births in Nigeria.

Adrenogenital Syndrome
Adrenogenital syndrome, also referred to as congenital adrenal hyperplasia, is due to the excessive secretion of androgens in the body. This can cause intense masculinising effects throughout the body.
In the male that has not undergone puberty, an adrenal tumor causes rapid development of the male sexual organs while in the adult male, the characteristics of adrenogenital syndrome are usually overshadowed by the normal post-puberty features in the body. Therefore, it is usually difficult to make a diagnosis of adrenogenital syndrome in the adult male.

If the phenomenon, however, occurs in a female, masculine characteristics develop, including growth of a beard, a much deeper voice, baldness (if she also has the genetic trait for baldness), masculine distribution of hair on the body and the pubis and growth of the clitoris to resemble a penis. Females that have congenital adrenal hyperplasia lack an enzyme responsible for the production of some hormones therefore causing the overproduction of androgens (the male hormone).

It is managed via hormone replacement medications throughout life. There are fewer than a hundred thousand cases per year in Nigeria.

These are just a few of the many diverse rare diseases that exist in our current age. As aspiring medics, it is important that while we mind the common things that occur commonly, we also endeavour to improve our clinical acumen on the less common cases. Some day, a life may depend on it.

Loveth Ayegboyin


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