Table 3.

Hereditary diseases in sheep: genetic mutations and inheritance types.

Disease / syndrome	Genetic cause/Mutation	Main symptoms	Breeds affected	Inheritance
Spider lamb Syndrome	Mutation in FGFR3 gene (codon 700)	Skeletal deformities, long limbs, lethality	Suffolk, Hampshire	Autosomal recessive
Entropion	Polygenic, some evidence on chromosome 15	Inward-turning eyelids, eye irritation	Swiss White Alpine, others	Polygenic
Cryptorchidism	Likely polygenic	Undescended testicle(s), infertility	Various	Polygenic
Congenital muscular dystrophy	Mutation in LAMA2 gene	Muscle weakness, stunted growth	Texel (rare)	Autosomal recessive
Dermatosparaxis (Ehlers-Danlos type)	Mutation in ADAMTS2 gene	Fragile, easily torn skin	White Dorper, Norwegian White	Autosomal recessive
Heritable cataracts	Likely associated with ovine chromosome 6	Clouded lens, impaired vision	Romney, Merino	Likely recessive or dominant
β-Mannosidosis	Deficiency of β-mannosidase enzyme	Neurological signs, developmental delay	Nubian goats, some sheep	Autosomal recessive