Clinical Characteristics of Arthrogryposis, Renal Tubular Dysfunction, Cholestasis(ARC) Syndrome in Korea

ABSTRACT

PURPOSE: ARC syndrome refers to an association of arthrogryposis, renal tubular dysfunction, and cholestasis. The VPS33B gene was recently identified as the causative gene. So far, 41 cases of ARC syndrome have been reported worldwide, and it has rarely been reported in Korea. This study was conducted to report the clinical findings of seven ARC syndrome cases in Korean children, focusing especially on renal tubular dysfunction. METHODS: The hospital records of 7 cases diagnosed as ARC syndrome at Severance Hospital between Mar. 1995 and Aug. 2005 were reviewed and analyzed. RESULTS: Of the 7 cases, 4 were boys and 3 were girls. Six patients(85%) were born with normal birth weight at term, and one was born at preterm. All cases presented with cholestasis and severe jaundice. According to the type of arthrogryposis described by Brown et al, type 3 and 4 were found in 2 patients and type 6, 7, and the undistributed type in one patient respectively. Other associated clinical findings were as followsfailure to thrive in 6(85%), lax skin in 5(71%), and gray platelet syndrome in 4(57%). Urine analysis revealed 6 cases(85%) with proteinuria, 3(43%) with hematuria, 5(71%) with glycosuria, 2(29%) with phosphaturia and 2(29%) with calciuria. Serum electrolytes showed 4 cases(57%) with hyponatremia, 3(43%) with hypokalemia, and 1(14%) with creatinine elevation. Renal tubular dysfunctions were diagnosed as renal tubular acidosis in 6 cases(85%), nephrogenic diabetes insipidus in 2(29%), and Fanconi syndrome in 2(29%). During the follow-up period, 2(29%) had no treatment, 5(85%) had continuous supplementation to correct the electrolyte imbalance and acidosis, and 1(14%) had dialysis. Only one patient had a family history of ARC syndrome in a sibling. Four cases(57%) were diagnosed at the mean age of 8.2 months, and one case was lost during follow-up. Ages of the survived 2 cases were 13 and 25 months, respectively. CONCLUSION: The rare disease of ARC syndrome is associated with severe renal dysfunction. However, this study revealed that the renal manifestation of ARC syndrome in Korean children is relatively mild and survival rate is higher than that of previous studies. Contrary to previous reports, this study showed that familial cases are rare and sporadic occurence is possible in Korea. Thus, the diagnosis of this syndrome requires a careful evaluation of the renal function in cases of congenital arthrogryposis, and a mandatory genetic counseling of affected family for prevention of familial occurance.