Biallelic variants in PAX3 cause Klein syndrome.

Waardenburg syndrome is a group of genetic conditions that can cause hearing loss and pigmentation deficiency of the hair, skin, and eyes. Klein-Waardenburg syndrome (Waardenburg syndrome type 3) represents a distinct presentation of Waardenburg syndrome type 1 and includes musculoskeletal abnormalities in addition to dystopia canthorum hearing loss and pigmentary changes. Heterozygous or homozygous variants in the PAX3 gene cause Klein-Waardenburg syndrome. Here we report on a new severely affected child, with a homozygous PAX3 variant (c.251C>T; p.Ser84Phe), review the features of the syndrome, and propose a new classification. The designation of Waardenburg syndrome should be given only to patients with monoallelic pathogenic variants in PAX3 whether or not musculoskeletal abnormalities are present. Patients with biallelic PAX3 variants should be outlined as a distinct group and designated Klein syndrome.

Brain abscess as a complication of nasopharyngeal COVID-19 swab testing: Two case reports and a literature review.

INTRODUCTION AND IMPORTANCE: The nasopharyngeal swab, which has experienced a marked increase in utilization during the COVID-19 pandemic and is considered the gold standard for COVID-19 testing due to its high diagnostic accuracy and sensitivity, The procedure is generally safe and well-tolerated, with pain, discomfort, and the urge to cough or sneeze being the most common complications. Though it is occasionally associated with serious complications. CASE PRESENTATION: we report two cases of brain abscess as a complication of nasopharyngeal COVID-19 testing. The first case was of a 47-year-old male diabetic patient with a positive medical history for immune thrombocytopenic purpura (ITP) who developed a frontal brain abscess one week after the swabbing procedure and was treated with systemic antibiotics followed by a successful functional endoscopic sinus surgery. The second case involved a hypertensive female patient in her 40s who also developed a frontal brain abscess on the same side as painful nasal COVID-19 testing. Systemic antibiotics were used to treat the patient. CLINICAL DISCUSSION: Serious adverse events from nasopharyngeal COVID-19 testing were reported to occur rarely, with incidences ranging from 0.0012 to 0.026 %. Retained swabs, epistaxis, and CSF leakage were commonly reported complications, which were frequently associated with high-risk factors such as septal deviations, pre-existing basal skull defects, and sinus surgeries. However, brain abscess complications are considered one of the extremely rare complications, with only a few cases reported in the literature. CONCLUSION: Appropriate approaches that depend on adequate anatomical knowledge are necessary for practitioners to perform nasopharyngeal COVID-19 testing.