About smith-mccort dysplasia

What is smith-mccort dysplasia?

Dyggve-Melchior-Clausen (DMC) syndrome is a rare, progressive genetic disorder characterized by abnormal skeletal development, microcephaly and intellectual disability. The condition was first reported by Dyggve, Melchior and Clausen in 1962 in three of eight siblings where the father was the mother's paternal uncle. Because of physical appearance and the present of acid mucopolysaccharides in the urine, Dyggve believed that their affected patients had Morquio-Ullrich disease (now Morquio syndrome). Skeletal abnormalities in this condition may include a barrel-shaped chest with a short truck, partial dislocation of the hips, genu valgum (knocked knees) or varum (bowed legs), and decreased joint mobility. In 11% of patients, there is atlantoaxial (upper neck vertebrae) instability that can lead to spinal cord compression, weakness and paralysis. Normally, there is growth deficiency resulting in short stature. Radiographic findings in older children and adults are pathognomonic for the disorder. DMC results from mutations in the DYM (dymeclin) gene and is inherited in an autosomal recessive mode.

A variant of DMC syndrome, Smith-McCort syndrome (SMS), which was first described by Smith and McCort in 1958, has identical skeletal abnormalities, but lacks the intellectual disability. SMS is also caused by mutations in DYM, and thus is allelic to DMC. Both are classified as osteochondrodysplasias, specifically a spondyloepimetaphyseal dysplasia; this latter category of dysplasias consists of 28 separate disorders.

What are the symptoms for smith-mccort dysplasia?

Spondyloepimetaphyseal dysplasias (SEMD) are a heterogeneous group of chondrodysplasias, characterized by different patterns of inheritance. Different subtypes of SEMD are reported in genetic medical databases and literature. The Smith-McCort variant syndrome (SMS) or smith-mccort dysplasia is one of the subtypes of SEMD (subtype II).

1. SMS is a rare autosomal recessive osteochondrodysplasia characterized by short limbs and a Short trunk with a barrel-shaped chest. Here we report a case of SMS, presenting characteristic orofacial and radiographic features.
2. The patients of SMS have a short trunk, dwarfism, a striking barrel-shaped chest, sternal protrusion, kyphoscoliosis, and various distal deformities, including genu valgum or varum.
3. The most striking radiographic findings are lacy iliac crest apophysis, hip dysplasia, platyspondyly, double vertebral hump, and odontoid hypoplasia, with atlantoaxial instability.
4. The diagnosis may be confirmed histologically, but no biochemical defect has been defined yet.
5. In SEMD, disturbed growth can be recognized by abnormal radiographic findings within the epiphyses of long bones, the adjacent metaphyses, and the vertebral bodies.
6. Patients may require orthopedic femoral osteotomy, total hip arthroplasty, early meniscectomy, realignment osteotomy, or posterior cervical spine fusion.
7. Short limbs and a barrel-shaped chest, with a normal mentality, in addition to double-humped vertebrae and an irregular lace-like appearance of the iliac crests, are pathognomonic for DMC and SMC.
8. Orodental findings are not often described with significance and include an everted lower lip, macroglossia, enamel hypoplasia, hypo calcification, prognathism, and decreased bone density. Our case showed the characteristic skeletal and dental abnormalities of SMC, confirmed by radiographic findings.
9. Other subtypes of SEMD include subtype I, which is DMV, subtype III (X-linked with mental retardation), subtype IV (SEMD with joint laxity), and subtype V (SEMD, Strudwick type), subtype VI (SEMD, hypotrichosis), and subtype VII.

Orofacial and radiographic features,The patients of SMS have a short trunk, dwarfism, a striking barrel-shaped chest, sternal protrusion, kyphoScoliosis
Dwarfism,A striking barrel-shaped chest,Sternal protrusion,Kyphoscoliosi
Symptomatic treatment and calcium supplements

What are the causes for smith-mccort dysplasia?

Smith McCort dysplasia is a genetic disease, which means that it is caused by one or more genes not working correctly.

Disease causing variants in the following gene(s) are known to cause this disease: DYM, RAB33B

What are the treatments for smith-mccort dysplasia?

Smith-McCort dysplasia (SMC) is a rare spondylo-epi-metaphyseal dysplasia characterized by the clinical manifestations of coarse facies, short neck, short trunk dwarfism with a barrel-shaped chest, and rhizomelic limb shortening, as well as specific radiological features (i.e., generalized platyspondyly with double-humped vertebral end plates and iliac crests with a lace-like appearance) and normal intelligence.

1. Management and treatment of disease often depend on the specific diagnosis and the type and severity of associated symptoms.
2. A primary care provider (PCP) can help coordinate care when multiple specialists are involved.
3. Understanding the risks and benefits of different options allows patients and families to play an active role in medical care decisions.
4. Ideally, published medical care guidelines are available for a diagnosed disease. Guidelines may include treatment options and tests needed to monitor symptoms or possible complications. But many rare diseases do not have medical guidelines because too little is known about the disease.
5. In these cases, a doctor may base their management and treatment recommendations on current medical research and their experience treating similar diseases.
6. The goal of managing symptoms is to improve the quality of life of patients by decreasing or eliminating troubling symptoms.
7. Treatment of symptoms (symptom management) may include medications, clinical procedures, diet management, physical, occupational, and speech therapy, or supportive care.
8. Symptom management may be recommended when there is no confirmed diagnosis or no disease-specific treatment, but it may also be suggested in addition to a disease-specific treatment.

Orofacial and radiographic features,The patients of SMS have a short trunk, dwarfism, a striking barrel-shaped chest, sternal protrusion, kyphoscoliosis
Dwarfism,A striking barrel-shaped chest,Sternal protrusion,Kyphoscoliosi
Symptomatic treatment and calcium supplements

What are the risk factors for smith-mccort dysplasia?

Smith-mccort dysplasia is an autosomal dominant disease. Autosomal means the gene is located on any chromosome except the X or Y chromosomes (sex chromosomes). Genes, like chromosomes, usually come in pairs. Recessive means that both copies of the responsible gene must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.

A person who has an autosomal recessive disease receives a gene with a pathogenic variant from each of their parents. Each parent is a carrier which means they have a pathogenic variant in only one copy of the gene. Carriers of an autosomal recessive disease usually do not have any symptoms of the disease. When two carriers of an autosomal recessive disease have children, there is a 25% (1 in 4) chance to have a child who has the disease.

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