SRD5A3

Kahrizi Syndrome

Clinical Characteristics

Ocular Features:

In an Iranian family with 3 affected sibs, cataracts (not further characterized) were noted in late adolescence. Iris colobomas, unilateral in one sib and bilateral in another, were present.

Systemic Features:

Children have severe psychomotor delays from birth and have severe mental retardation. Speech and normal motor function never develop fully. Thoracic kyphosis begins in late childhood and contractures develop in the elbows and knees. A CAT scan in one patient revealed only normal findings. Facial features have been described as ‘coarse’ with prominent lips, broad nasal bridge, and a bulbous nose. Some individuals with this condition have lived into the 5^th decade. Ataxia is usually present although the cerebellum may be normal on MRI.

Genetics

This is an autosomal recessive condition resulting from homozygous mutations in the SRD5A3 gene (4q12).

Kahrizi syndrome is allelic to CDG1Q, or congenital disorder of glycosylation type Iq (612379), an autosomal recessive disorder with mutations in the same gene and a partially overlapping ocular phenotype.

At least 10 families have been reported with mutations in this gene considered important to glycosylation.

Pedigree:

Autosomal recessive

Treatment

Treatment Options:

No specific treatment is available for this condition although physical therapy and cataract surgery might be considered in specific individuals.

References

Article Title:

Next generation sequencing in a family with autosomal recessive Kahrizi syndrome (OMIM 612713) reveals a homozygous frameshift mutation in SRD5A3

Kahrizi K, Hu CH, Garshasbi M, Abedini SS, Ghadami S, Kariminejad R, Ullmann R, Chen W, Ropers HH, Kuss AW, Najmabadi H, Tzschach A. Next generation sequencing in a family with autosomal recessive Kahrizi syndrome (OMIM 612713) reveals a homozygous frameshift mutation in SRD5A3. Eur J Hum Genet. 2011 Jan;19(1):115-7.

PubMed ID:

20700148

SRD5A3 is required for converting polyprenol to dolichol and is mutated in a congenital glycosylation disorder

Cantagrel V, Lefeber DJ, Ng BG, Guan Z, Silhavy JL, Bielas SL, Lehle L, Hombauer H, Adamowicz M, Swiezewska E, De Brouwer AP, Bl?omel P, Sykut-Cegielska J, Houliston S, Swistun D, Ali BR, Dobyns WB, Babovic-Vuksanovic D, van Bokhoven H, Wevers RA, Raetz CR, Freeze HH, Morava E, Al-Gazali L, Gleeson JG. SRD5A3 is required for converting polyprenol to dolichol and is mutated in a congenital glycosylation disorder. Cell. 2010 Jul 23;142(2):203-17.

PubMed ID:

20637498

An autosomal recessive syndrome of severe mental retardation, cataract, coloboma and kyphosis maps to the pericentromeric region of chromosome 4

Kahrizi K, Najmabadi H, Kariminejad R, Jamali P, Malekpour M, Garshasbi M, Ropers HH, Kuss AW, Tzschach A. An autosomal recessive syndrome of severe mental retardation, cataract, coloboma and kyphosis maps to the pericentromeric region of chromosome 4. Eur J Hum Genet. 2009 Jan;17(1):125-8.

PubMed ID:

18781183

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