Human RECQ Helicase Pathogenic Variants, Population Variation and "Missing" Diseases.

Area of Science:

• Genetics
• Molecular Biology
• Human Disease

Background:

• Heritable loss-of-function mutations in BLM, WRN, and RECQL4 cause Bloom, Werner, and Rothmund-Thomson syndromes.
• These syndromes are characterized by cancer predisposition and developmental or progeroid features.

Purpose of the Study:

• To systematically analyze genetic variation in all five human RECQ helicase genes.
• To understand RECQ pathogenic and population variation.
• To identify potentially pathogenic variants in RECQL and RECQL5.

Main Methods:

• Systematic analysis of genetic variation across all five human RECQ helicase genes.
• Identification of 3,741 unique base pair-level variants at 17,605 potential mutation sites.
• Utilized biochemical data, model organism data, and computational predictions.

Main Results:

• Identified over 300 potentially pathogenic population variants in RECQL and RECQL5.
• No individuals were found homozygous for any verified or predicted pathogenic RECQL or RECQL5 variant.
• No individuals were found heterozygous for known pathogenic variants in two or more of BLM, RECQL4, or WRN.

Conclusions:

• Several postulated RECQ helicase deficiency syndromes may be missing because they are likely incompatible with life.
• The absence of homozygous RECQL/RECQL5 pathogenic variants and compound heterozygous BLM/RECQL4/WRN pathogenic variants suggests severe genetic constraints.
• Further research is needed to fully elucidate the spectrum of RECQ helicase-related disorders.