Diseases

Microcephaly pontocerebellar hypoplasia dyskinesia

Microcephaly - pontocerebellar hypoplasia - dyskinesia: A rare, recessively inherited disorder characterized by an abnormally small brain and brainstem which manifests as a small head and mental retardation. The brain progressively degenerates.

Microcephaly- primary autosomal recessive

Microcephaly, primary autosomal recessive: A rare, recessively inherited condition characterized by a small head. The 6 forms of this condition differ with respect to the origin of the genetic defect involved. The size of the brain often reduces in size with age with many cases resulting in death before the age of 30 years.

Microcoria- congenital

Microcoria, congenital: A very rare disorder where the muscles that dilate the pupils don't develop normally or are completely absent and the pupils have little or no ability to dilate.

Microdontia hypodontia short stature

Microdontia - hypodontia - short stature: A rare disorder characterized by small teeth, missing teeth and short stature, strabismus and borderline mental deficiency.

Microencephaly

Microcephaly is a neurodevelopmental disorder. It serves as an important neurological indication or warning sign, but no uniformity exists in its definition. It is usually defined as a head circumference (HC) more than two standard deviations below the mean for age and sex. Some academics advocate defining it as head circumference more than three standard deviations below the mean for the age and sex. Microcephaly may be congenital or it may develop in the first few years of life. The disorder may stem from a wide variety of conditions that cause abnormal growth of the brain, or from syndromes associated with chromosomal abnormalities. A homozygous mutation in one of the microcephalin genes causes primary microcephaly.

In general, life expectancy for individuals with microcephaly is reduced and the prognosis for normal brain function is poor. The prognosis varies depending on the presence of associated abnormalities.

Microgastria limb reduction defect

Congenital microgastria limb reduction defect: A rare syndrome characterized by micrograstia and limb reduction as well as other abnormalities.

Microhydranencephaly

Microhydranencephaly (MHAC) is a severe abnormality of brain development characterized by both microcephaly and hydranencephaly. Signs and symptoms may include severe microcephaly, scalp rugae (a series of ridges), and profound developmental delay. Familial occurrence of the condition is very rare but it has been reported in a few families. It has been suggested that MHAC is possibly inherited in an autosomal recessive manner.

Micromelic dysplasia- congenital- with dislocation of radius

Borochowitz et al. (1991) described 2 pairs of sibs, offspring of consanguineous couples from an Arabic-Moslem kindred, who presented at birth with severe short-limb dwarfism and distinct facial and radiologic appearance similar to that of patients 4 and 5 of Maroteaux et al. (1989) in their report of an apparently autosomal dominant congenital bone disorder that they called omodysplasia (164745). Borochowitz et al. [1991a] reported four children from a consanguineous Arab family from Israel with this new bone dysplasia and pointed out two other cases from the literature. Amale child, product of consanguineous Baluchi parents, was diagnosed as having this rare bone dysplasia. A sib with similar features died at 15 days of age.

Microphthalmia

Microphthalmia (or microphthalmos) means small eyes. In mammals the failure of expression of a transcription factor, MITF (microphthalmia-associated transcription factor), in the pigmented retina prevents this structure from fully differentiating. This in turn causes a malformation of the choroid fissure of the eye, resulting in the drainage of vitreous humor fluid. Without this fluid, the eye fails to enlarge, thus the name microphthalmia.

Microphthalmia cataract

Microphthalmia - cataract: A very rare syndrome characterized mainly by small eyes and cataracts.

Microphthalmia- isolated- with corectopia

Usher (1921) described a family with microphthalmia, myopia, corectopia, and microcornea in 11 members over 4 generations. Six family members also had rotatory nystagmus. There were 3 instances of male-to-male transmission.