RIDDLE syndrome is a rare genetic syndrome. The name is an acronym for Radiosensitivity, ImmunoDeficiency Dysmorphic features and Learning difficulties.
Presentation The features of this condition include:
Facial dysmorphism Short stature Mild motor control and learning difficulties Mild ataxia Microcephaly Normal intelligence Conjunctival telangiectasia Recurrent sinus infections Decreased serum IgA Late onset of pulmonary fibrosis Increased alpha-fetoprotein Increased radiosensitivity
Genetics This condition is due to mutations in the RNF168 gene. It is inherited in an autosomal recessive fashion. The gene encodes a ubiquitin ligase and is located on the long arm of chromosome 3 (3q29) on the Crick (minus strand).
Diagnosis
Differential diagnosis The DDx is
Ataxia telangectasia Artemis deficiency Immunodeficiency 26 (PKCS gene deficiency) LIG4 syndrome Nijmegen breakage syndrome Severe combined immunodeficiency with Cernunnos X-linked agammaglobulinemia
Management
Epidemiology This condition is extremely rare. Only four cases have been described up to 2017.
History This syndrome was first described by Stewart et al. 2007.
References