Utilization of genetic testing: Analysis of 4,499 prior authorization requests for molecular genetic tests at four US regional health plans.

Continuous advances in genetic testing methodologies and an increased understanding of the genetic mechanisms of diseases have fueled genetic testing utilization across health care specialties. To our knowledge, national trends in the ordering of genetic testing have not been studied broadly across clinical indications, testing methodologies, and ordering provider specialties. We performed a retrospective analysis of 4,499 complete prior authorization requests for molecular genetic testing submitted to four regional health plans' commercial lines of business between May 1, 2019 and May 31, 2019. Ordering providers were characterized by their certification(s) and specialty of practice. Among 4,499 genetic testing requests, 92% were ordered by non-genetics providers. Obstetrician/gynecology (OBGYN) (63%), oncology (15%), and genetics (8%) providers ordered genetic testing most frequently. Reproductive, hereditary cancer, and tumor testing were the most frequently ordered genetic tests. Seventy-nine percent of all prior authorization requests were approved. When analyzing complex genetic testing requests, we found that testing ordered by genetics providers was more likely to be approved based on health plan policy than testing ordered by non-genetics providers. Our results suggest that health care providers across multiple medical specialties may benefit from involvement of genetics specialists in decision-making regarding molecular tests.

CRB2 mutations produce a phenotype resembling congenital nephrosis, Finnish type, with cerebral ventriculomegaly and raised alpha-fetoprotein.

We report five fetuses and a child from three families who shared a phenotype comprising cerebral ventriculomegaly and echogenic kidneys with histopathological findings of congenital nephrosis. The presenting features were greatly elevated maternal serum alpha-fetoprotein (MSAFP) or amniotic fluid alpha-fetoprotein (AFAFP) levels or abnormalities visualized on ultrasound scan during the second trimester of pregnancy. Exome sequencing revealed deleterious sequence variants in Crumbs, Drosophila, Homolog of, 2 (CRB2) consistent with autosomal-recessive inheritance. Two fetuses with cerebral ventriculomegaly and renal microcysts were compound heterozygotes for p.Asn800Lys and p.Trp759Ter, one fetus with renal microcysts was a compound heterozygote for p.Glu643Ala and p.Asn800Lys, and one child with cerebral ventriculomegaly, periventricular heterotopias, echogenic kidneys, and renal failure was homozygous for p.Arg633Trp in CRB2. Examination of the kidneys in one fetus showed tubular cysts at the corticomedullary junction and diffuse effacement of the epithelial foot processes and microvillous transformation of the renal podocytes, findings that were similar to those reported in congenital nephrotic syndrome, Finnish type, that is caused by mutations in nephrin (NPHS1). Loss of function for crb2b and nphs1 in Danio rerio were previously shown to result in loss of the slit diaphragms of the podocytes, leading to the hypothesis that nephrosis develops from an inability to develop a functional glomerular barrier. We conclude that the phenotype associated with CRB2 mutations is pleiotropic and that the condition is an important consideration in the evaluation of high MSAFP/AFAFP where a renal cause is suspected.