A Family of LBR Biallelic Pathogenic Variants Resulting in Rhizomelic Skeletal Dysplasia with Pelger-Huët Anomaly.

Introduction: The lamin-B receptor (LBR) gene has two primary functions: maintaining the structural integrity of the nuclear envelope and playing a role in cholesterol biosynthesis. Heterozygous variants in the LBR gene have been associated with Pelger-Huët anomaly (PHA, OMIM #169400), while homozygous or compound heterozygous mutations have been associated with rhizomelic skeletal dysplasia, with or without PHA (OMIM #618019) and Greenberg dysplasia (OMIM #215140).

Case presentation: We report a 4-year-old boy presenting with short stature and short limbs and his mother exhibiting milder findings. Genetic analysis revealed a heterozygous c.1640A>G (p.Asn547Ser) and c.43C>T (p.Arg15*) variants in the LBR gene in both the boy and his mother. The father was identified as a heterozygous carrier of the c.43C>T (p.Arg15*) variant. Peripheral blood smears confirmed the PHA in the patient and his parents.

Conclusion: The phenotypic differences observed between the mother and male child in our study highlight the genetic variability and regressive nature of LBR-related skeletal dysplasias. This report shows the complexity of LBR-related phenotypes and expands the clinical spectrum of LBR mutations in rhizomelic skeletal dysplasia with PHA.