ESPN 51th Annual Meeting

ESPN 2018


 
COMPLEMENT FACTOR B MUTATION IN ATYPICAL HEMOLYTIC UREMIC SYNDROME; A CASE PRESENTATION
Aslı Çelebi Tayfur 1 Aysun Çaltık Yılmaz 1 Yasemin İnan 2 Ecem Karaokur 2 Bahar Büyükkaragöz 1 Mesut Koçak 2 Fatih Süheyl Ezgü 3

1- UNIVERSITY OF HEALTH SCIENCES, KEÇIÖREN TRAINING AND RESEARCH HOSPITAL, DEPARTMENT OF PEDIATRIC NEPHROLOGY
2- UNIVERSITY OF HEALTH SCIENCES, KEÇIÖREN TRAINING AND RESEARCH HOSPITAL, DEPARTMENT OF PEDIATRICS
3- GAZİ UNIVERSITY, FACULTY OF MEDICINE, DEPARTMENT OF PEDIATRICS, DIVISION OF GENETICS AND MOLECULAR DIAGNOSIS
 
Introduction:

Gain of function mutations of complement factor B (CFB)  are rare, with a frequency of 1%–3% of the patients with complement mediated hemolytic uremic syndrome (HUS). CFB mutation leads to a continuous activation of the alternative complement pathway.

 

Material and methods:

 We present here a case of an 6 years-old boy diagnosed with atypical HUS associated with a heterozygous mutation in CFB gene.

 

Results:

An 6 years old boy was admitted to our hospital with acute generalised jaundice and malaise. Results of the patient’s blood work were consistent with microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury.  The family history revealed that his brother also suffered an episode of atypical HUS of unknown origin without recurrence. New Generation DNA Sequencing  of the atypical HUS susceptibility genes [CFH, CFH-related protein 3, CFI, MMACHC (methylmalonic aciduria and homocystinuria type C protein), DGKE (diacylglycerol kinase ε)and CFB] revealed a heterozygous mutation [c.1408+11 A>C (Z:509:482)] in the CFB gene of our patient. The Human Splicing Finder Programme predicted a low probability of splicing alteration for this mutation. The patient was treated with fresh frozen plasma (FFP) infusions (20 ml/kg/day).  His renal functions gradually improved but  he experienced a second HUS episode 1 month after discharge and he was again treated with FFP infusions (20 ml/kg/day). He has been followed up at Pediatric Nephrology Outpatient Clinic with normal kidney functions.

Conclusions:

CFB mutations are associated with poor outcomes. Progression to ESRD occurs in 70 percent of patients. The presence of a heterozygous CFB mutation did not led a poor prognosis in our patient. Phenotype-genotype correlations and outcome are need to be investigated in more numbers of CFB-mutated aypical HUS patients.