Mutations in the MT-CYB gene found in mitochondrial DNA can cause mitochondrial complex III deficiency. When caused by mutations in this gene, the condition is usually characterized by muscle weakness (myopathy) and pain, especially during exercise (exercise intolerance).
Hejazi Arabic, also known as Western Arabian Arabic, is a variant of the Arabic language spoken predominantly in the western region of Saudi Arabia. The language is spoken by approximately 8 million Saudi nationals, as of the last census.
The diversity of the ethnic makeup of Yemen is reflected in the languages spoken, with many indigenous languages used throughout the country. The official language of Yemen is Modern Standard Arabic, as established by Article 2 of the 1991 constitution. This language is spoken by approximately 17.7 million individuals, and is the language of government services, media broadcasts, and public education. In addition to the Modern Standard variety, at least 5 other spoken dialects of Arabic are also used throughout the country.