Diseases

Methylmalonyl-Coenzyme A mutase deficiency

Methylmalonicaciduria results from an autosomal recessive inherited genetic defect in methylmalonic CoA mutase (MCM), an enzyme required for the proper metabolism of some protein components, cholesterol, and fatty acids. As a result of a deficiency in MCM, methylmalonic acid accumulates in the bloodstream and urine, causing a severe metabolic disorder that may lead to death. Treatment consists chiefly of diet modification and the administration of several medications that may counteract this process

Mevalonic aciduria

Mevalonic aciduria, also called mevalonate kinase deficiency, is an autosomal recessive metabolic disorder that disrupts the biosynthesis of cholesterol and isoprenoids.

Meyenburg-Altherr-Uehlinger syndrome

Meyenburg-Altherr-Uehlinger syndrome: A rare disorder characterized by recurring inflammation of cartilage which results in deterioration of the cartilage. Any part of the body with cartilage may be affected - ears, nose bridge, larynx, trachea, aortic heart valve and around joints. Symptoms are determined by the part of the body that is affected. Breathing problems and even death can occur if the cartilage in the breathing airways or the aortic valve are affected.

MHC class 1 or class 2 deficiency

MHC class 1 or class 2 deficiency: An inherited immunodeficiency disorder involving a deficiency of class I and II major histocompatibility complexes. Serious infections can result. Immunology. 1996 May; 88(1): 124–129. PMCID: PMC1456472 Copyright notice Impact of donor MHC class I or class II antigen deficiency on first- and second-set rejection of mouse heart or liver allografts. S Qian, F Fu, Y Li, L Lu, A S Rao, T E Starzl, A W Thomson, and J J Fung Department of Surgery, University of Pittsburgh Medical Center, PA, USA. Small right arrow pointing to: This article has been cited by other articles in PMC. Abstract The influence of donor major histocompatibility complex (MHC) class I- or class II-deficiency on the initiation of first- and second-set rejection of mouse heart and liver allografts was examined. C3H (H-2k) mice received heterotopic cardiac or orthotopic liver grafts from unmodified B10 (H-2b), B6 (H-2b), b2m (H-2b; class I deficient) or AB0 (H-2b; class II deficient) donors. Organ survival was also investigated in C3H recipients that had been presensitized by a normal B10 skin graft 2-3 weeks before heart or liver transplantation. The absence of cell surface MHC class I or class II resulted in significant prolongation of primary cardiac allograft survival. Three of seven (43%) MHC class I-deficient, and two of five (40%) class II-deficient heart grafts were accepted indefinitely (survival time > 100 days). Thus both MHC class I and class II molecules appear to be important for the elicitation of first-set rejection in the heart allograft model. All liver allografts survived > 100 days in normal recipients. In C3H recipients that had been presensitized by a B10 skin graft, however, both heart and liver grafts from AB0 (class II deficient) donors underwent accelerated rejection (median survival time [MST] 3 and 4 days, respectively). In contrast, liver grafts from class I-deficient mice (b2m) were still accepted indefinitely by B10 skin-presensitized C3H recipients, whereas class I-deficient hearts survived significantly longer than those from class II-deficient or normal donors. These data demonstrate that the expression of donor MHC class I, and not class II is crucial in initiating second-set organ allograft rejection. In vitro monitoring revealed that at the time of organ transplant, both splenocytes and serum of the skin-presensitized animals displayed high cytotoxicity against AB0 (class II-deficient) but not against b2m (class I-deficient) targets.

Michelin tire baby syndrome

Michelin Tire Baby Syndrome (also known as "Folded skin with scarring" ), is characterized by multiple, symmetric, circumferential skin creases, or bands, on the forearms, lower legs, and often the neck that are present at birth. The creases disappear later in life. They are reminiscent of these of the mascot of the tire manufacturer, Michelin, hence the name of the syndrome. Associated abnormalities vary and may include facial dysmorphism, upslanting palpebral fissures, hypertelorism, cleft palate, genital anomalies, mild developmental delay, ureterocele, smooth muscle hamartoma, nevus lipomatosus, Laron syndrome (dwarfism with high growth hormone and low somatomedin activity), and other defects. It was originally described by Ross in 1969. Twenty cases of this hamartomatous disorder have been reported.

Michels Caskey syndrome

Michels-Caskey syndrome: A very rare disorder characterized by underdeveloped thumbs, spine deformities and lack of development of the female reproductive organs such as the uterus and vagina (mullerian duct aplasia). The external genitalia may appear to be normal.

Mickleson syndrome

Mickleson syndrome: A very rare syndrome characterized mainly by mental retardation and facial and skull anomalies.

Micrencephaly corpus callosum agenesis

The development of the corpus callosum depends on a large number of different cellular and molecular mechanisms. These include the formation of midline glial populations, and the expression of specific molecules required to guide callosal axons as they cross the midline. An additional mechanism used by callosal axons from neurons in the neocortex is to grow within the pathway formed by pioneering axons derived from neurons in the cingulate cortex. Data in humans and in mice suggest the possibility that different mechanisms may regulate the development of the corpus callosum across its rostrocaudal and dorsoventral axes. The complex developmental processes required for formation of the corpus callosum may provide some insight into why such a large number of human congenital syndromes are associated with agenesis of this structure.

Micro syndrome

Micro syndrome: A rare, recessively inherited disorder characterized by intellectual impairment, small head, various eye problems, small genitals and abnormal brain development.

Microbrachycephaly ptosis cleft lip

Microbrachycephaly - ptosis - cleft lip: A very rare syndrome characterized mainly by a small, short head, droopy eyelids and a cleft lip.

Microcephalic osteodysplastic primordial dwarfism- type 1

Microcephalic osteodysplastic primordial dwarfism, type 1: A form of dwarfism associated with brain and skeletal abnormalities. The clinical and radiological findings in a pair of sibs with microcephalic osteodysplastic primordial dwarfism (MOPD) are described, a boy who survived for 5 1/2 years and his more severely affected younger sister, who died at the age of 6 months. Neuropathological studies in this girl showed marked micrencephaly with severely hypoplastic, poorly gyrated frontal lobes and absent corpus callosum. Our observation supports the hypothesis that types I and III MOPD probably constitute a spectrum of one and the same entity and published data together with this report are consistent with autosomal recessive inheritance. The pathogenesis of this condition is as yet unknown, but its characteristics indicate a basic defect affecting cell proliferation and tissue differentiation.

Microcephalic primordial dwarfism

Primordial dwarfism is a rare form of dwarfism that results in a smaller body size in all stages of life beginning from before birth. More specifically, primordial dwarfism is a diagnostic category including specific types of profoundly proportionate dwarfism, in which individuals are extremely small for their age, even as a fetus. Most individuals with primordial dwarfism are not diagnosed until they are about 3 years of age. Medical professionals typically diagnose the fetus as being small for the gestational age, or as having intrauterine growth retardation when an ultrasound is conducted. Typically, people with primoridal dwarfism are born with very low birth weights. After birth, growth continues at a stunted rate, leaving individuals with primordial dwarfism perpetually years behind their peers in stature and in weight. Most cases of short stature are caused by skeletal or endocrine disorders. The five subtypes of primordial dwarfism are the most severe forms of the 200 types of dwarfism, and it is estimated that there are only 100 individuals in the world with the disorder. Other sources list the number of persons currently afflicted as high as 100 in North America.[citation needed] It is rare for individuals affected by primordial dwarfism to live past the age of 30. In the case of microcephalic osteodysplastic primordial dwarfism (MOPD) type II there can be increased risk of vascular problems, which may cause premature death.

Microcephaly

Microcephaly describes a head size significantly below normal for a person's age and sex, based on standardized charts. Head size is measured as the distance around the top of the head.

Microcephaly autosomal dominant

Microcephaly, autosomal dominant: A very rare inherited disorder characterized mainly by a small head, short stature and other anomalies.

Microcephaly cardiomyopathy

In 1991, Winship et al1 described South African sibs, one male child aged 5 years and one female child aged 12 months, with a combination of microcephaly, dilated cardiomyopathy, and minor dysmorphic features. The cardiomyopathy had resolved in the older child by the age of 3 years, and had markedly improved in the younger child on treatment for associated cardiac failure. The microcephaly was severe, and both children showed severe global developmental delay. The dysmorphic features were described as cupping of the outer helix of both pinnae, fifth finger clinodactyly, and sandal gaps on both feet. The older sib had fine pigmentary stippling at the posterior poles and macula of the fundus on ophthalmological examination.