Clinical and variant spectrum of patients harboring ATAD3A variants.

Background: ATAD3A deficiency may lead to respiratory chain deficits. This observational study aimed to summarize the clinical features and variant spectrum of patients harboring ATAD3A variants.

Methods: We examined patients harboring ATAD3A variants who attended the Children's Hospital of Zhejiang University School of Medicine, further examined similar cases reported in the literature, analyzed the clinical and variation data.

Results: Five new patients harboring ATAD3A variants were encountered at Children's Hospital of Zhejiang University School of Medicine. New phenotypes including noncompaction of ventricular myocardium and recurrent asphyxia were observed. Whole-exome sequencing revealed six new variants, including c.1376T>C, c.649G>A, c.1492dup, and three copy number variants. In total, data from 88 patients harboring ATAD3A variants were collected, including those from our center, but only 31.8% were alive at the last follow-up. In total, 54 variants were identified, with deletions being the most common variant type. Moreover, 29 variants were detected in more than one patient, and the top three most common were g.1391996_1460043 duplication, c.1582C>T, and c.229C>G. Among the 88 patients, 38 (43.2%) had a monoallelic variant and 50 (56.8%) had biallelic variants; additionally, 64 (72.7%) had severe variants and 24 (27.3%) had mild variants. In the monoallelic group, hyperlactatemia (50.0% vs. 95.0%; P=0.02), seizures (22.2% vs. 84.6%; P=0.007), and death (7.7% vs. 96.0%; P<0.001) were more common in patients with severe variants than in those with mild variants. Dysmorphic facies were more common in patients with mild variants in both the monoallelic (90.0% vs. 38.5%; P=0.03) and biallelic (100.0% vs. 38.9%; P=0.02) groups. Monoallelic patients were less likely to have abnormal brain development than biallelic patients, in both the mild (18.2% vs. 100.0%; P=0.001) and severe (18.2% vs. 77.1%; P<0.001) groups. Meanwhile, in patients with severe variants, hypertrophic cardiomyopathy was more common in monoallelic patients than biallelic patients (73.9% vs. 38.1%; P=0.02).

Conclusions: Our patients have expanded the variant spectrum and clinical landscape in patients harboring ATAD3A variants. The clinical course of patients harboring ATAD3A variants is related to the variant type. Prenatal genetic consultation is necessary in families with ATAD3A variants.