Background: Bicuspid aortic valve (BAV) is the most common congenital heart defect with a prevalence of 1%–2% in the general population. NOTCH1, SMAD6, and GATA5 are associated with BAV in humans, but few cases have been reported that did not involve NOTCH1. Here, we identified novel in‐frame variants in SMAD6 (c.1168_1173dup; p.Gly390_Ile391dup) in a BAV patient, who presented with dilatation of the ascending aorta and severe calcification of the aortic valve.Methods: Twenty BAV associated genes were screened by exome sequencing. Functional effects of SMAD6 variant were investigated using bone morphogenetic protein (BMP) signaling assays through in vitro functional study.Results: Exome sequencing revealed he had novel in‐frame variants in the SMAD6 gene (c.1168_1173dup; p.Gly390_Ile391dup). SMAD6 is known to be an inhibitory protein in the BMP signaling pathway. In vitro functional study of the p.Gly390_Ile391dup variant revealed impaired inhibition of BMP signaling and BMP‐induced alkaline phosphatase activity.Conclusion: In conclusion, we identified a novel SMAD6 variant causing a severely calcified BAV and TAA, which contributes to our understanding of the clinical and genetic background of SMAD6‐related BAV.

Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by progressive proximal muscle weakness and atrophy. Given the recent introduction of gene therapies, knowledge of the SMA carrier frequency in various populations has become important for developing screening programs for this disease. In total, 1,581 anonymous DNA samples from an umbilical cord blood bank were tested for SMN1 and SMN2 gene copies using a multiplex ligation-dependent probe amplification assay. Twenty-nine of the 1,581 newborns [1.83%; 95% confidence interval (CI), 1.25-2.66%] were SMA carriers with one copy of SMN1, and no homozygous SMN1 deletion was detected. The carrier frequency in this population was estimated to be 1,834 per 100,000 (95% CI, 1,254-2,659) or 1 in 55 (95% CI, 1/79-1/38). Our data indicate that SMA carriers are not uncommon in the Korean population and may serve as a reference for designing a population screening program in Korea.

Background Aromatic L-amino acid decarboxylase (AADC) deficiency is an autosomal recessive neurotransmitter metabolism disorder and is clinically characterized by infancy hypotonia, ophthalmic crisis, and developmental delay. With the emergence of gene therapy for AADC deficiency, accurate prediction of AADC deficiency is required. This study aimed to analyze the carrier frequency and expected incidence of AADC deficiency using exome data from the Genome Aggregation Database (gnomAD). Methods We analyzed 125,748 exomes from gnomAD, including 9197 East Asian exomes, for the DDC gene. All identified variants were classified according to the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines. Results The worldwide carrier frequency of AADC deficiency was 0.17%; the highest frequency was observed in East Asians at 0.78%, and the lowest was in Latinos at 0.07%. The estimated incidence of AADC deficiency was 1 in 1,374,129 worldwide and 1 in 65,266 in East Asians. Conclusion The results demonstrated that East Asians have a higher carrier frequency of AADC deficiency than other ethnic groups. The variant spectrum of DDC genes in East Asian populations differed greatly from those of other ethnic groups. Our data will serve as a reference for further investigation of AADC deficiency. Impact This study analyzed exome data from the Genome Aggregation Database (gnomAD) to estimate the carrier frequency and expected incidence of aromatic L-amino acid decarboxylase (AADC) deficiency. The article provides updated carrier frequency and incidence estimates for AADC deficiency, particularly in East Asian populations, and emphasizes the significant differences in the variant spectrum of DDC genes in this population compared to other ethnic groups. The study provides important information for accurate prediction and early diagnosis of AADC deficiency, particularly in high-risk populations, and may aid in the development of more effective targeted screening programs and gene therapies for this disorder.

Jong Eun Park, M.D., Ph.D., Taeheon Lee, Ph.D., Eun Hye Cho, M.D., Ph.D., Mi-Ae Jang, M.D., Ph.D., Dongju Won, M.D., Ph.D., Boyoung Park, M.D., Ph.D., Chang-Seok Ki, M.D., Ph.D., and Sun-Young Kong, M.D., Ph.D.. Ann Lab Med -0001;0:. https://doi.org/10.3343/alm.2024.0242

Background: Inherited retinal diseases (IRDs) are clinically and genetically heterogenous disorders leading to visual impairment and blindness. Because gene therapy for RPE65-associated IRDs was recently approved, it is necessary to predict the carrier frequency and prevalence for RPE65-associated IRDs. This study aimed to analyze the carrier frequency and expected incidence of RPE65-associated IRDs in East Asians and Koreans using exome data from the Genome Aggregation Database (gnomAD) and the Korean Reference Genome Database (KRGDB). Methods: We analyzed 9,197 exomes for East Asian populations from gnomAD comprising 1,909 Korean and 1,722 Korean genomes from KRGDB. All identified RPE65 variants were classified according to the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines. Results: The total carrier frequencies of East Asians and Koreans from both gnomAD and KRGDB were 0.10% (11/10,919) and 0.06% (2/3,631), respectively. The estimated incidence of RPE65-associated IRDs was 1/3,941,308 in East Asians and 1/13,184,161 in Koreans. Conclusion: This study identified carrier frequencies of RPE65-associated IRDs in East Asians and Koreans using gnomAD and KRGDB. We confirmed that the carrier frequency of RPE65-associated IRDs patients was low in Koreans among all East Asian populations, and the incidence was also predicted to be lower than in other East Asian populations. The variant spectrum of RPE65 gene in East Asian and Korean populations differed greatly from those of other ethnic groups.