Variants in FREM1 and trisomy 18 identified in a neonatal progeria patient

BACKGROUND

Neonatal progeroid disorders are rare disorders with clinical features including low body mass index, proptosis, aged and dysmorphic facial features at the time of birth, prominent veins, sparse scalp hairs, and severe growth retardation. Very few cases have been identified with an unknown genetic cause. Here, we report clinical and genetic findings of a proband with hallmark features of neonatal progeria.

METHODS

Microarray comparative genomic hybridization, whole exome sequencing (WES) and Sanger sequencing were performed using standard methods.

RESULTS

Array combined genome hybridization data revealed trisomy 18 in the proband (II-1), and WES data identified novel compound heterozygous variants (c.247 C > T; p.H83Y and c.14769868InsA) in the FREM1 gene.

CONCLUSION

We report a novel complex case of neonatal progeria with atrial septal defects, trisomy 18 without typical features of Edward syndrome. The phenotype of the patient was more consistent with neonatal progeria, thus we speculate it to be caused by the FREM1 variants.

Neonatal progeroid variant of Marfan syndrome with congenital lipodystrophy results from mutations at the 3' end of FBN1 gene

We report a 16-year-old girl with neonatal progeroid features and congenital lipodystrophy who was considered at birth as a possible variant of Wiedemann-Rautenstrauch syndrome. The emergence of additional clinical signs (marfanoid habitus, severe myopia and dilatation of the aortic bulb) lead to consider the diagnosis of the progeroid variant of Marfan syndrome. A de novo donor splice-site mutation (c.8226+1G>A) was identified in FBN1. We show that this mutation leads to exon 64 skipping and to the production of a stable mRNA that should allow synthesis of a truncated profibrillin-1, in which the C-terminal furin cleavage site is altered. FBN1 mutations associated with a similar phenotype have only been reported in four other patients. We confirm the correlation between marfanoid phenotype with congenital lipodystrophy and neonatal progeroid features (marfanoid-progeroid-lipodystrophy syndrome) and frameshift mutations at the 3' end of FBN1. This syndrome should be considered in differential diagnosis of neonatal progeroid syndromes.