ALGS is caused by loss of function mutations in either JAG1 (Jagged1) or NOTCH2 (Notch homolog 2). In the majority of people with ALGS, the gene mutation occurs in the JAG1 gene. The JAG1 mutation is either intragenic and found on chromosome 20p12, or it is a deletion of the entire JAG1 gene. Mutations in NOTCH2 are much less likely to cause<unk> , but the primary type of ALGS-causing mutation in NOTCH2 is a missense mutation. A missense mutation is a point mutation that changes one nucleotide, which results in a codon that codes for the wrong amino acid.<unk>  is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to cause the disorder. The "autosomal" aspect of the disease means that the gene mutation occurs in an autosome, which is one of the 44 chromosomes in the human body that is not a sex chromosome (chromosome X or Y). Although the majority of cases are due to the autosomal dominant gene, there have been reports of a rare, autosomal recessive version of the disease. In the autosomal recessive case, the ALGS patient must inherit two mutated genes: one from each parent. Although about 40% of the mutations are inherited from affected parents, most cases result from new, acquired mutations. These are caused by environmental factors that mutate one copy of the gene. Environmental factors that can result in gene mutations may include radiation such as ultraviolet rays from the sun, or chemicals such as benzene, which is found in cigarette smoke. These cases occur in people with no familial history of the disorder.
Alagille syndrome
DiGeorge syndrome
Treacher Collins syndrome
LIG4 syndrome
MEDNIK syndrome
GRACILE syndrome
Kabuki syndrome
Hajdu–Cheney syndrome