Genetic disorders with no OMIM

thumb|Black squirrel|Melanistic black [[eastern grey squirrel (Sciurus carolinensis)]] thumb|Melanistic guinea pigs (Cavia porcellus) are rare, and are used in rituals by Andean [[curanderos.]]

thumb|right|Leucistic white lions owe their colouring to a recessive allele. Note the eyes and lips remain the normal colour. Studies have shown that the reduced pigment comes from a mutation in the gene for [[tyrosinase, the same as causes Type I oculocutaneous albinism in humans.]] thumb|right|alt=All-white dominant white horse with pink skin, brown eyes, and white hooves.|This white (horse)|white horse owes its coloring to a dominant allele ([[dominant white).]] thumb|A leucistic rock dove. Both the eyes and legs are still of the normal colour. Leucism () or leukism, is a wide variety of co

hair loss due to susceptibility of hair follicles to androgenic miniaturization

genetically and clinically heterogeneous group of neurodegenerative disorders characterized by progressive spasticity and hyperreflexia of the lower limbs

bone remodeling disease that results in the destruction of normal bone and replacing it with fibrous bone tissue

Human disease

Xanthochromism (also called xanthochroism or xanthism), from the Greek xanthos (ξανθός) "yellow" and chroma (χρώμα) "color", is an unusually yellow pigmentation in an animal. It is often associated with the lack of usual red pigmentation and its replacement with yellow. The cause is usually genetic but may also be related to the animal's diet. The opposite of xanthochromism, a deficiency in or complete absence of yellow pigment, is known as axanthism.

thumb|This green-striped grasshopper is not very green due to erythrism. thumb|An erythristic Welsh polecat Erythrism or erythrochroism refers to an unusual reddish pigmentation of an animal's hair, skin, feathers, or eggshells.

congenital absence of the fibula

medical condition

congenital hemolytic anemia characterized by ineffective erythropoiesis, and resulting from a decrease in the number of red blood cells (RBCs) in the body and a less than normal quantity of hemoglobin in the blood

Nullisomic is a genetic condition involving the lack of both the normal chromosomal pairs for a species (2n-2). Humans with this condition will not survive.

right|thumb|Often called "Albinism|albino", this amelanistic [[Burmese python owes its yellow color to unaffected carotenoid pigments.]] Amelanism (also known as amelanosis) is a pigmentation abnormality characterized by the lack of pigments called melanins, commonly associated with a genetic loss of tyrosinase function. Amelanism can affect fish, amphibians, reptiles ,(including birds) and mammals including humans. The appearance of an amelanistic animal depends on the remaining non-melanin pigments. The opposite of amelanism is melanism, a higher percentage of melanin.

Microorchidism is a genetic disorder found in males, characterized by abnormally small testicles; it is the opposite of macroorchidism, which is characterized by abnormally large testicles. The condition is associated with (and often secondary to) a number of other genetic disorders, including Klinefelter syndrome and Prader-Willi syndrome, as well as other multiple malformation disorders. The degree of abnormality (or otherwise) of the testes can be determined by the use of an orchidometer. In addition, microorchidism may also occur as a result of shrinkage or atrophy of the testis due to inf

Hemimelia is a birth defect consisting in unilateral or bilateral underdevelopment of the distal part of the lower or upper limb. The affected bone may be shortened or not develop at all.

Autosomal genetic disorder most prevalent in the American Paint Horse.