Lysosomal acid lipase deficiency (LALD) is a rare, chronic, progressive disease based on a defect in the LIPA gene encoding lysosomal acid lipase, early diagnosis of which may be difficult due to the diversity of the clinical picture. The purpose of the study. To evaluate the early clinical and laboratory symptoms of LALD, the timing of manifestation and diagnosis in patients of the Moscow region. Materials and methods. The analysis of the medical documentation of 6 patients with a confirmed diagnosis of lysosomal acid lipase deficiency by the results of enzyme diagnostics and DNA-diagnostics registered in the Moscow region: 5 children aged 2 to 16 years, one patient aged 19 years. Boys - 3, girls - 3. Results. In 3 patients (50%), the first symptoms of the disease were detected before the age of 1 year, in two children (33%) - from 1 to 2 years, in one child - at the age of 5 years. The most common early clinical symptom was cytolysis syndrome and hepatosplenomegaly, less often dyspeptic manifestations (flatulence, diarrhea). The average age of onset of the disease is 1.5 years. The duration of follow-up ranged from 1 year to 14 years. On average, the duration of the diagnostic search was 6.75 years, and the average age of diagnosis was 8.25 years. At the time of diagnosis confirmation, all patients showed signs of hepatosplenomegaly, diffuse changes in liver parenchyma, increased serum transaminases, hypercholesterolemia, increased LDL and decreased HDL. Excess of ALT values up to 2 norms was diagnosed in one child (17%), from 2 to 3 norms - in 3 children (50%), from 3 to 5 norms - in 2 children (33%). AST is less than 2 norms - in 2 children (33%), from 2 to 3 norms - in 3 (50%), in 1 child - 5-6 norms (17%). The absolute majority of patients (83%) had c894G>A mutations in the LIPA gene in a homozygous state. Conclusion. LALD is a rare disease, the diagnosis of which is difficult due to the frequent asymptomatic course or non-specific clinic. In most children, the disease manifests at an early age (up to 3-5 years), and the most common symptoms are increased liver transaminases and hepatosplenomegaly. ALT and AST activity, as a rule, does not exceed 2-3 norms. The signs characteristic of DL are detected randomly during examination for other diseases. Due to the non-specificity of clinical symptoms, the duration of diagnosis varies from several months to several years. The main modern method of diagnosing LALD is enzyme diagnostics and DNA diagnostics. If a child has hepatolienal syndrome, a persistent increase in markers of cytolysis and dyslipidemia, caution should be exercised and the necessary diagnostic examinations should be carried out in a timely manner to exclude LALD.