RIDDLE syndrome
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 on the Crick.Diagnosis
Differential diagnosis
The DDx is- Ataxia telangectasia
- Artemis deficiency
- Immunodeficiency 26
- LIG4 syndrome
- Nijmegen breakage syndrome
- Severe combined immunodeficiency with Cernunnos
- X-linked agammaglobulinemia