Genetics Topics:

1. Introduction
   1. Impact of inbreeding within the Habsburg family.
      1. Inbreeding is a common practice in royal families.
   1. The Spanish line of the Habsurg family being Extinct 
   1. Mandibular prognathism also known as the “Habsburg Jaw”.
2. Overview of the Habsburg Royal Family
   1. Lineage ended at the end of the 17th century
      1. King Charles II ended up having no children despite being married twice, thus deemed infertile.
      1. 29.4% of children born in the Habsburg family died before the age of one, and 50% died at the age of 10.
      1. The family, overall, had a high mortality rate due to the number of inbreeding.
      1. The family also suffered from a lot of psychological, neurological, and physical disorders.
   1. The family kept inter-marrying and interbreeding with each other.
      1. Within a two-hundred year period, more than eleven incestuous marriages were contracted by the Habsburgs.
      1. Prevalence of incestuous marriages have been ongoing for more than 300 years.
   1. King Charles II
      1. He was the last king of the Habsburg dynasty.
      1. He also was a really sick and frail monarch as a result of all of the inbreeding.
      1. Suffered from Aspartylglucosaminuria, sporadic hematuria and intestinal problems.
      1. Autopsy from after he died also showed that his heart was extremely small, his head was filled with water, and a single testicle that was black.
         1. This could be due to the Aspartylglucosaminuria.
3. Habsburg Jaw
   1. Characterized as a strong square-shaped jaw.
      1. Caused many health issues such as excessive drooling, difficulty eating, and speech impairment as a result of the shape of the jaw.
      1. Also caused disfiguration around the face such as the flat nose, round forehead, as well as a big tongue.
   1. May either be due to maxillary regression rather than mandibular prognathism.
   1. Many members of the family also have inherited this jaw.
      1. Carlos II of Spain and Philip IV of Spain being two people that prominently have this jaw.
      1. Potentially developed into an autosomal dominant trait within the Habsburg family due to the number of individuals in the family that have inherited the disease.
4. Aspartylglucosaminuria
   1. Is an autosomal recessive disorder in which glycoasparagines are deposited and build up in several different tissues.
      1. Prevalent in populations that engage in a high degree of incest.
   1. Characteristics include normal pregnancy and birth
      1. However, delayed motor development, speech development, and intellectual disabilities by toddler ages.
   1. Other characteristics
   1. Many members of the family died by the age of 50.
      1. Mortality rate increased significantly as a result of inbreeding.
5. Conclusion
   1. As a result of the inbreeding, the Habsburgs family ended up suffering from many genetic disorders.
      1. This is due to many mutations becoming more apparent and becoming more of a dominant trait as a result.

Works Cited:

Alvarez, G., Ceballos, F. C. & Quinteiro, C. The role of inbreeding in the extinction of a European royal dynasty. PLoS ONE 4, (2009).

Ceballos, F. C. & Álvarez, G. Royal dynasties as human inbreeding laboratories: The Habsburgs. Heredity 111, 114–121 (2013).

Martin, A., Heard, R. & Fung, V. S. Carlos II of Spain, ‘The bewitched’: Cursed by aspartylglucosaminuria? BMJ Neurology Open 3, (2021).