Schimke immunoosseous dysplasia (SIOD) is characterized by spondyloepiphyseal dysplasia (SED) resulting in disproportionate short stature, nephropathy, and T-cell deficiency.
How common is SIOD?
SIOD is very rare with an incidence of 1 case per 1-3 million.
What is the molecular basis of SIOD?
Schimke immunoosseous dysplasia (SIOD) is an autosomal recessive disease due to SMARCAL1 gene mutation.
SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a-like 1, also known as SMARCAL1, is a human gene. The protein encoded by this gene is a member of the SWI/SNF family of proteins. The SMARCAL1 protein convert RPA-bound, single stranded DNA into double-stranded DNA, an enzyme activity termed "annealing helicase".
Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands (i.e. DNA, RNA, or RNA-DNA hybrid) using energy derived from nucleotide hydrolysis.
What is the life expectancy in SIOD?
The life expectancy is 9 years.
What is the cause of death in SIOD?
ESRD, stroke, and CHF. Generally, the patients do not succumb to life-threatening infections secondary to immunodeficiency.
Schimke Immunoosseous Dysplasia. University of Washington, Seattle.
SMARCAL1, from Wikipedia, the free encyclopedia.
Helicase, from Wikipedia, the free encyclopedia.
Image source: Structure of E. coli helicase RuvA, Wikipedia, GNU Free Documentation License.