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Q&A

Genetics

Poster Session 4

(1152) Positive Carrier Screening for Alport Syndrome: A Need for Greater Awareness

Wednesday, February 14, 2024

1:00 PM – 2:30 PM

Location: Prince George's Exhibit Hall CDE, Lower Atrium Level

Primary & Presenting Author(s)

Vivienne Souter, MD

Research Director, Obstetrical Care Outcomes Assessment Program
Foundation for Health Care Quality
Seattle, WA, United States

Coauthor(s)

LJ

Lisa Johnson, MS

Natera, Inc.
Austin, TX, United States
SK

Sarah Keilman, MS

Natera, Inc.
Austin, TX, United States
EB

Emily Becraft, MS

Natera, Inc.
Austin, TX, United States
ER

Elizabeth Repass, MS

Natera, Inc.
Austin, TX, United States
BP

Brittany Prigmore, MS

Natera, Inc.
Austin, TX, United States
YW

Yang Wang, PhD

Natera, Inc.
Austin, TX, United States
HT

Hossein Tabriziani, MD

Director of Organ Transplant
Natera, Inc.
Austin, TX, United States
PB

Peter Benn, DSc

University of Connecticut Health Center
Farmington, CT, United States

Objective: Alport syndrome can be inherited as an autosomal recessive, dominant or X-linked condition. COL4A3 and COL4A4 genes are included in some carrier screening panels due to their association with autosomal recessive Alport syndrome. Carriers for pathogenic (P) or likely pathogenic (LP) variants in these genes have a frequency of approximately 1 in 279 and 1 in 332, respectively (Souter et al., Obstet Gynecol; In Press), and these individuals can also express symptoms, including hematuria and progressive renal disease. We present follow up data for pregnant people identified through carrier screening as carriers for P/LP variants in one of these two genes.

Study Design: This retrospective observational study included follow-up of pregnant people (aged 18-55 years) identified as heterozygous for a P/LP variant in COL4A3 or COL4A4 through a 274 gene panel ordered from a US commercial laboratory (01/2020-09/2022). Pregnancy outcomes were requested from providers offices. Data were de-identified prior to analysis. Pre-pregnancy health, hematuria, specialist consults, and pregnancy complications were evaluated.

Results: To date, outcomes are available for 76 pregnant people: 45 were heterozygous for a COL4A3 variant and 31 for a COL4A4 variant. Hematuria or a pre-pregnancy history of renal disease was present in 6.6% and pre-pregnancy hypertension was reported in 3.9%, but only a minority of patients with these symptoms had a nephrology referral. Preeclampsia in the most recent pregnancy was reported in 11.8%. Overall, 1 in 15 patients were referred to a nephrologist, 13 (17.1%) to maternal fetal medicine, and 23 (30.3%) were referred for comprehensive genetic counseling.

Conclusion: Our preliminary data showing low specialist referral rates suggest that the potential for developing Alport syndrome in people identified as carriers might not be widely recognized among obstetric professionals. The significance of symptoms such as hematuria might not be recognized and the opportunity for nephrology care and early intervention could be missed.