NBAS disease: 14 new patients, a recurrent mutation, and genotype-phenotype correlation among 24 Chinese patients

Neuroblastoma amplified sequence (NBAS)-associated disease has a wide phenotypic spectrum, including infantile liver failure syndrome type 2 (ILFS2, OMIM #616483), short stature with optic nerve atrophy and Pelger-Huët anomaly (SOPH) syndrome (OMIM #614800), and a combined phenotype overlapping ILFS2 and SOPH syndrome. The mutation spectra of NBAS and its genotype-phenotype correlation among Chinese were not clear.

Clinical and genetic data were retrospectively collected from the medical charts of patients with biallelic NBAS mutations, as well as from Chinese patients in previously published reports.

Fourteen new patients were identified, including 10 novel mutations: c.648-1G>A, c.2563_c.2577+5del/p.His855_Gln859del, c.3115C>T/p.Gln1039Ter, c.3284G>A/p.Trp1095Ter, c.2570C>T/p.Ala857Val, c.6859G>T/p.Asp2287Tyr, c.1028G>A/p.Ser343Asn, c.1177_1182delinsAGATAGA/p.Val393ArgfsTer2, c.3432_3435dupCAGT/p.Ala1146GlnfsTer14, and c.680_690dupACTGTTTCAGC/p.Phe231ThrfsTer35. All 14 patients presented as fever-triggered liver injury, including nine patients that satisfied the criteria of acute liver failure (ALF) in whom c.3596G>A/p.Cys1199Tyr occurred five times. Nine patients had extrahepatic manifestations including short stature, skeletal abnormalities, intellectual disability, ophthalmic abnormalities, low levels of serum immunoglobulins, facial dysmorphism, and cardiac abnormalities. Ten other Chinese patients were collected through a review of published works. Genotype-phenotype analysis in 24 Chinese patients revealed that the percentage of ALF patients with variants in the Sec39 domain was significantly higher than that in the C-terminal (100% vs. 12.5%, P = 0.000), and the percentage of multi-organ/system involvement in patients with variants in the Sec39 domain was significantly lower than that in the C-terminal (40% vs. 100%, P = 0.0128).

We reported 14 new patients, 10 novel mutations, and a unique recurrent mutation. Correlation analysis indicated that the domain of missense and non-frameshift insertion/deletion mutations in NBAS protein is related to phenotype among Chinese patients.