Cooks syndrome is a hereditary disorder which is characterized in the hands by bilateral nail hypoplasia on the thumb, index finger, and middle finger, absence of fingernails (anonychia) on the ring finger and little finger, lengthening of the thumbs, and bulbousness of the fingers. In the feet, it is characterized by absence of toenails and absence/hypoplasia of the distal phalanges. In the second study of this disorder, it was found that the intermediate phalanges, proximal phalanges, and metacarpals were unaffected.The disorder was first described by Cooks et al. in 1985 after being discovered in two generations of one family. It was proposed that the inheritance of the disorder is autosomal dominant. A second family, this with three affected generations, confirmed that the inheritance of the disorder is autosomal dominant. Although several genetic disorders exist which can cause anonychia and onychodystrophy, such disorders often cause other anomalies such as deafness, mental retardation, and defects of the hair, eyes, and teeth. Cooks syndrome is not known to cause any such anomalies.In 1999, a pair of siblings was found with brachydactyly type B. Because the disorder primarily affected the nails and distal phalanges, the research group concluded that brachydactyly type B and Cooks syndrome are the same disorder. However, in 2007, a 2-year-old girl was found with symptoms consistent with both brachydactyly type B and Cooks syndrome. It was found that the two syndromes were distinct clinically, radiologically, and genetically. Notes


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In the same year Jabs et al. reported a family that over two generations had granulomatous synovitis, uveitis and cranial neuropathies. The condition was transmitted in an autosomal dominant fashion.Then in 1990 Pastores et al. reported a kindred with a phenotype very similar to what Blau described and suggested that the condition be called Blau Syndrome (BS). They also pointed out the similarities in the families noted above to BS but also pointed out the significant differences in the phenotypes.In 1996 Tromp et al. conducted a genome wide search using affected and non affected members of the original family. A marker, D16S298, gave a maximum logarithm of odds (LOD) score of 3.75 and put the BS susceptibility locus within the 16p12-q21 interval. Hugot et al. found a susceptibility locus for Crohn disease, a granulomatous inflammation of the bowel, on chromosome 16 close to the locus for BS. Based on the above information Blau suggested in 1998 that the genetic defect in BS and Crohn Disease might be the same or similar. Finally in 2001 Miceli-Richard et al. found the defect in BS to be in the nucleotide-binding domain of CARD15/NOD2. They commented in their article that mutations in CARD15 had also been found in Crohns disease. Confirmation of the defect in BS being in the CARD15 gene was made by Wang et al. in 2002 using the BS family and others.