X-LRT

X-LRT applies a likelihood-based test to detect associations of markers and haplotypes on the X chromosome and to estimate disease-related marker relative risks in case-parents and nuclear family designs.

Key Features:

• Likelihood-Based Approach: X-LRT estimates genetic relative risks and performs hypothesis testing for X-linked markers using a likelihood framework.
• Case-Parents Design: Tailored to nuclear families with an affected proband and their parents, and it accommodates additional siblings and missing parental genotypes.
• Single Marker and Haplotype Testing: Supports single-marker association tests and haplotype-based analyses under assumptions of random mating and multiplicative penetrance.
• Flexibility in Penetrance Relationships: Allows testing of different penetrance relationships within and between sexes to address sex-specific X-linked inheritance patterns.
• Efficiency with Incomplete Data: Leverages sibling genotype information to improve efficiency when parental genotypes are missing.
• Simulation-Based Performance Assessment: Employs simulated data to evaluate power and type I error rates.

Scientific Applications:

• Parkinson's disease family studies: Applied to investigate associations in families affected by Parkinson's disease, including analyses of markers within the monoamine oxidase A&B genes.
• X-linked complex disorders: Used to explore X-linked genetic contributions to various complex disorders by estimating relative risks and testing genotype associations.

Methodology:

Likelihood-based statistical testing applied within a case-parents/nuclear family framework, with simulated datasets used to evaluate power and type I error rates and with accommodation for missing parental genotypes and additional siblings.