Background: Primary lactose intolerance (PLI) is a gradual decrease of lactase activity that usually manifests at the age of 1-5 years. It has been proved that PLI is related to a single-nucleotide polymorphism of the lactase (LCT) gene. Objective: An evaluation was performed on the usefulness of genetic tests in detecting LCT 13910C>T and 22018G>A polymorphisms in diagnosing lactose intolerance in children. Methods: The study group included 99 children aged from 2 months to 16.5 years with different digestive tract symptoms. In all patients a hydrogen breath test (HBT) was conducted and blood samples were collected to determine LCT polymorphisms. PLI was defined as the presence of the 13910CC and/or 22018GG polymorphism in patients with a positive HBT result. Results: In the group younger than 6 years, no statistically significant correlation was observed between the 13910CC and/or 22018GG LCT polymorphisms and HBT result. In the group of children older than 6, a statistically significant correlation between the 13910CC (p ¼ 0.0011) and 22018GG (p ¼ 0.003) LCT polymorphisms and HBT result was detected. Conclusions: In children older than 6, the result of genetic testing based on LCT 13910C>T and 22018G>A polymorphisms may diagnose lactose intolerance.

Background: Pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) is a novel entity. The inflammatory process involves the circulatory, digestive, respiratory, and central nervous systems, as well as the skin. Making a diagnosis requires extensive differential diagnoses, including lung imaging. The aim of our study was to retrospectively assess the pathologies found in lung ultrasound (LUS) in children diagnosed with PIMS-TS and to evaluate the usefulness of the examination in diagnostics and monitoring. Methods: The study group consisted of 43 children diagnosed with PIMS-TS, in whom LUS was performed at least three times, including on admission to hospital, on discharge, and 3 months after disease onset. Results: Pneumonia (mild to severe) was diagnosed in 91% of the patients based on the ultrasound image; the same number had at least one pathology, including consolidations, atelectasis, pleural effusion, and interstitial or interstitial-alveolar syndrome. By the time of discharge, the inflammatory changes had completely regressed in 19% of the children and partially in 81%. After 3 months, no pathologies were detected in the entire study group. Conclusion: LUS is a useful tool for diagnosing and monitoring children with PIMS-TS. Inflammatory lesions of the lungs resolve completely when the generalized inflammatory process subsides.

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