Progress toward discerning the genetics of cleft lip

Area of Science:

• Genetics
• Developmental Biology
• Public Health

Background:

• Orofacial clefts are common birth defects with significant genetic influences.
• Nonsyndromic orofacial clefts present as isolated defects, categorized into cleft lip with or without cleft palate, and cleft palate only.
• The genetic complexity of these traits has historically hindered the identification of specific disease loci and genes.

Purpose of the Study:

• To review recent advancements in human genetic studies focused on identifying causal genes for isolated or nonsyndromic cleft lip with or without cleft palate.
• To provide an overview of the current understanding of the genetic architecture of nonsyndromic orofacial clefts.

Main Methods:

• Review of human genetic studies, including genome scans and meta-analyses.
• Analysis of candidate gene approaches.
• Consideration of emerging technologies like genome-wide association studies and sequencing.

Main Results:

• Genome scans and meta-analyses have identified novel genetic loci associated with nonsyndromic orofacial clefts.
• Candidate gene studies have highlighted the significant roles of IRF6 and MSX1 in the etiology of these conditions.
• Currently, no causal mutations with definitively described functional effects have been identified.

Conclusions:

• Genome-wide association studies and cost-effective sequencing are expected to accelerate the identification of disease-causing genes.
• Future research will focus on characterizing gene-environment and gene-gene interactions.
• This knowledge is crucial for improving risk counseling and developing effective preventive strategies for orofacial clefts.