1q21.1 deletion syndrome is a rare aberration of chromosome 1. A human cell has one pair of identical chromosomes on chromosome 1. With the 1q21.1 deletion syndrome, one chromosome of the pair is not complete, because a part of the sequence of the chromosome is missing. One chromosome has the normal length and the other is too short. In 1q21.1, the 1 stands for chromosome 1, the q stands for the long arm of the chromosome and 21.1 stands for the part of the long arm in which the deletion is situated. The syndrome is a form of the 1q21.1 copy number variations, and it is a deletion in the distal area of the 1q21.1 part. The CNV leads to a very variable phenotype, and the manifestations in individuals are quite variable. Some people who have the syndrome can function in a normal way, while others have symptoms of intellectual impairment and various physical anomalies.1q21.1 microdeletion is a very rare chromosomal condition. Only 46 individuals with this deletion have been reported in medical literature as of August 2011.
: 440 Additionally, the various skin changes associated with onchocerciasis may be described as follows:: 440 
Leopard skin
The spotted depigmentation of the skin that may occur with onchocerciasis: 440 
Elephant skin
The thickening of human skin that may be associated with onchocerciasis: 440 
Lizard skin
The thickened, wrinkled skin changes that may result with onchocerciasis: 441

Prevention
Various control programs aim to stop onchocerciasis from being a public health problem. The first was the Onchocerciasis Control Programme (OCP), which was launched in 1974, and at its peak, covered 30 million people in 11 countries. Through the use of larvicide spraying of fast-flowing rivers to control black fly populations, and from 1988 onwards, the use of ivermectin to treat infected people, the OCP eliminated onchocerciasis as a public health problem. The OCP, a joint effort of the World Health Organization, the World Bank, the United Nations Development Programme, and the UN Food and Agriculture Organization, was considered to be a success, and came to an end in 2002. Continued monitoring ensures onchocerciasis cannot reinvade the area of the OCP. Elimination
In 1995, the African Programme for Onchocerciasis Control (APOC) began covering another 19 countries, mainly relying upon the use of the drug ivermectin. Its goal was to set up community-directed treatment with ivermectin for those at risk of infection. In these ways, transmission has declined. APOC closed in 2015 and aspects of its work taken over by the WHO Expanded Special Programme for the Elimination of Neglected Tropical Diseases (ESPEN).