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DP-LHX3

Pituitary Dwarfism

Name:	Pituitary Dwarfism – Shepherd Type
Gene Location:	LHX3
Chromosome:	9
Mutation:	c.622-37-31del
Symptom Complex:	Systemic
Inheritance:	Autosomal recessive
Test type:	Direct mutation test
Typical onset age:	6-12 weeks

Note: these information are only valid for Tibetan Terriers.

General Information
Pituitary Dwarfism is a genetic disorder characterized by a severe lack of multiple pituitary hormones due to a defect in the LHX3 gene, which is essential for the proper development of the pituitary gland, motor neurons, and inner ear. It is characterized by a combined deficiency of growth hormone (GH), thyroid-stimulating hormone (TSH), prolactin, and gonadotropins. Due to this mutation, the pituitary glands of affected dogs fail to develop normally, leading to a deficiency of multiple hormones essential for growth and development. DP-LHX is 7-base pair (7-bp) deletion in intron 5 of the LHX3 gene.

General Information

Pituitary Dwarfism is a genetic disorder characterized by a severe lack of multiple pituitary hormones due to a defect in the LHX3 gene, which is essential for the proper development of the pituitary gland, motor neurons, and inner ear. It is characterized by a combined deficiency of growth hormone (GH), thyroid-stimulating hormone (TSH), prolactin, and gonadotropins. Due to this mutation, the pituitary glands of affected dogs fail to develop normally, leading to a deficiency of multiple hormones essential for growth and development. DP-LHX is 7-base pair (7-bp) deletion in intron 5 of the LHX3 gene.

Clinical features
Retarded Growth: Disproportionate dwarfism (size is much smaller than littermates). Coat Abnormalities: Retention of puppy coat, bilateral symmetrical alopecia (hair loss on trunk/neck), and skin hyperpigmentation. Developmental Delays: Delayed eruption of permanent teeth, shrill bark, and often delayed epiphyseal closure. Endocrine Deficiencies: Low levels of growth hormone (GH), thyroid-stimulating hormone (TSH), prolactin, and impaired release of gonadotropins. Neurological/Structural Issues: Some cases develop atlanto-axial instability (a joint defect in the neck). Reduced Life Expectancy: Often 4–5 years, though some may live longer with hormone replacement therapy (porcine GH and l-thyroxine). However the prognosis often results in a poor quality of life, which may lead to euthanasia. Please note that symptoms and age-frames may also be of other types and may differ from those mentioned above.

Clinical features

Retarded Growth:
Disproportionate dwarfism (size is much smaller than littermates).
Coat Abnormalities:
Retention of puppy coat, bilateral symmetrical alopecia (hair loss on trunk/neck), and skin hyperpigmentation.
Developmental Delays:
Delayed eruption of permanent teeth, shrill bark, and often delayed epiphyseal closure.
Endocrine Deficiencies:
Low levels of growth hormone (GH), thyroid-stimulating hormone (TSH), prolactin, and impaired release of gonadotropins.
Neurological/Structural Issues:
Some cases develop atlanto-axial instability (a joint defect in the neck).
Reduced Life Expectancy:
Often 4–5 years, though some may live longer with hormone replacement therapy (porcine GH and l-thyroxine). However the prognosis often results in a poor quality of life, which may lead to euthanasia.

Please note that symptoms and age-frames may also be of other types and may differ from those mentioned above.

Morbidity
CLEAR / N/N		CLEAR / N/N = Dogs with N/N genotype will not have this disease.
CARRIER / N/DP-LHX3		CARRIER / N/DP-LHX3 = Dogs with N/DP-LHX3 genotype are generally clinically healthy and do not develop the disease.
AFFECTED / DP-LHX3/DP-LHX3		AFFECTED / DP-LHX3/DP-LHX3 = Dogs with DP-LHX3/DP-LHX3 dogs can appear normal at birth, but begin to exhibit clinical effects in short time. By 6 weeks, a notable difference in weight and height is typically observed, though full diagnostic signs may be more obvious closer to 8-12 weeks.

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Inheritance