Chondrodysplasia Grebe type is a rare

genetic disorder A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders ...

. It is caused by a mutation to the

GDF5 Growth/differentiation factor 5 is a protein that in humans is encoded by the ''GDF5'' gene. The protein encoded by this gene is closely related to the bone morphogenetic protein (BMP) family and is a member of the TGF-beta superfamily. This gro ...

gene. This mutation may be inherited in an

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the Phenotype, effect of a different variant of the same gene on Homologous chromosome, the other copy of the chromosome. The firs ...

pattern.

Signs and symptoms

Chondrodysplasia Grebe type causes both

dwarfism Dwarfism is a condition of people and animals marked by unusually small size or short stature. In humans, it is sometimes defined as an adult height of less than , regardless of sex; the average adult height among people with dwarfism is . '' ...

and dysmelia (short limb deformity). It may also cause dental problems. There is significant phenotypic variability between individuals. At birth, patients with Grebe-type chondrodysplasia display severe dwarfism. Afflicted individuals may also experience severe shortening and deformities of the long bones, fusion or absence of carpal and tarsal bones, ball shaped fingers, polydactyly, and absent joints.

Cause

Chondrodysplasia Grebe type is caused by a mutation to the

gene. It is inherited in an

pattern. Because of this, 60% of people with chondrodysplasia Grebe type have consanguinous

parent A parent is either the progenitor of a child or, in humans, it can refer to a caregiver or legal guardian, generally called an adoptive parent or step-parent. Parents who are progenitors are First-degree relative, first-degree relatives and have ...

Diagnosis

Due to the small number of

signs and symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

, and rarity, chondrodysplasia Grebe type is hard to diagnose.

Genetic testing Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...

, usually

exome sequencing Exome sequencing, also known as whole exome sequencing (WES), is a genomic technique for sequencing all of the protein-coding regions of genes in a genome (known as the exome). It consists of two steps: the first step is to select only the subs ...

, is used to identify the mutation to the

gene.{{Cite web, title=Chondrodysplasia, Grebe Type - Tests - GTR - NCBI, url=https://www.ncbi.nlm.nih.gov/gtr/tests/256850/, access-date=2021-04-14, website=www.ncbi.nlm.nih.gov

References

Genetic diseases and disorders