Caroli disease and syndrome are a group of rare liver diseases. Caroli disease is a congenital malformation characterized by segmental, non-obstructive fibrocystic enlargement of the intrahepatic bile ducts. Caroli syndrome is a combination of dilatation of the intrahepatic bile ducts and congenital liver fibrosis. The frequency of this pathology is less than 1 case per 100,000 in the population. This disease is hereditary with an autosomal recessive type of inheritance associated with a mutation in the PKHD1 gene, which encodes a fibrocystin/polyductin protein complex, which is expressed in the cortical and cerebral ducts of the kidneys, as well as in the bile and pancreatic ducts.

This article presents a clinical case of Caroli syndrome in a boy O., aged 1 year 7 months. The boy was born from the second pregnancy and the first childbirth (the first pregnancy resulted in a missed abortion at 7 weeks). Delivery by Cesarean section at 41 weeks of pregnancy. The child was born with a body weight of 4400 g, body length of 54 cm. Mother was 31 years old, father was 37 years old. At the time of hospitalization at the age of 1 year and 7 months, the child's condition was considered moderate.

Results of objective examination: weight is 10 kg, height is 75 cm. The skin is clean and pale. There is a delay in physical development.

Examination revealed stigmas of dysembryogenesis: dolichocephalic shape of the head, wide nose bridge, hypertelorism, deep crease under the big toe. No pathology of the respiratory and cardiovascular systems was detected during the examination. The abdomen is enlarged. The liver protrudes from the edge of the costal arch by 4cm, the spleen by 2cm. According to the data of the laboratory study, iron deficiency anemia of the 1st degree was detected. In order to exclude hepatitis, tests for HbsAg of hepatitis B virus, total antibodies IgG and IgM against HCV, antibodies IgM against cytomegalovirus were conducted, all test results were negative. Given the presence of hepatosplenomegaly, the stigma of dysembryoenesis, the child, in addition to traditional examinations, was prescribed examinations in order to exclude diseases of lysosomal accumulation and disorders of amino acid metabolism. Thus, diseases of accumulation from the group of sphingomyelinosis and hereditary metabolic diseases caused by metabolic disorders of amino acids and acylcarnitines were excluded in the child.

Karyotype of the child: 46,XY, t(9;10)(p10;p10)[15] Male karyotype with reciprocal translation of the whole arms of chromosomes 9 and 10.