Genetic Etiologies, Diagnosis, and Management of Neonatal Cystic Kidney Disease.

Fetal kidney development is a complex and carefully orchestrated process. The proper formation of kidney tissue involves many transcription factors and signaling pathways. Pathogenic variants in the genes that encodethese factors and proteins can result in neonatal cystic kidney disease. Advancements in genomic sequencing have allowed us to identify many of these variants and better understand the genetic underpinnings for an increasing number of presentations of childhood kidney disorders. This review discusses the genes essential in kidney development, particularly those involved in the structure and function of primary cilia, and implications of gene identification for prognostication and management of cystic kidney disorders.

Hemoglobin Sunshine Seth: A Case Report of Low-Oxygen-Affinity Hemoglobinopathy.

Pulse oximetry is routinely used in the newborn nursery for clinical monitoring and to detect critical congenital heart disease. The differential diagnoses for reduced peripheral oxygen saturation in an infant include congenital heart disease, respiratory distress syndrome, transient tachypnea of the newborn, persistent pulmonary hypertension of the newborn, meconium aspiration syndrome, pneumonia, pneumothorax, and sepsis. The diagnostic evaluation for neonatal hypoxemia can be invasive and expensive. When this evaluation is unrevealing, other interventions may be tried without clear benefit to the patient, including, but not limited to, supplemental oxygen. Therefore, it is important to consider alternative, albeit rare, diagnoses, including hemoglobinopathies with abnormal oxygen binding properties. Mutations in the structure of alpha- and beta-globin chains can alter the affinity of hemoglobin for oxygen, and changes in oxygen affinity may result in changes in the oxygen saturation detected by pulse oximetry. These changes may or may not be of clinical significance. This case report describes Hemoglobin Sunshine Seth, a rare low-oxygen-affinity hemoglobin variant presenting as reduced peripheral oxygen saturation in an otherwise well-appearing infant male.