Possibly relevant human trait(s) and/or gene(s)s (MIM numbers): 274400 (trait) , 601843 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Recessive

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2018

Species-specific symbol: CDHG

Inheritance: Soler Arias et al. (2018): "Congenital dyshormonogenic hypothyroidism with goiter in this family [of Shih-Tzu] is an autosomal recessive trait."

Molecular basis: Soler Arias et al. (2018): "A homozygous mutation of the intron 9 splice acceptor site of SLC5A5 gene, encoding the sodium/iodine symporter (NIS), was found in the DNA of one of the affected dogs [the only one from whom a DNA sample could be obtained; the other one having died]. The mutation was a single base transition of guanine > adenine (G > A) at position 45,024,672 of dog chromosome 20 (CFA20). Five of eight healthy dogs, including both parents of one of the dogs exhibiting CDHG, were heterozygous A/G, and the other 3 were homozygous for the wild-type allele G/G. No sequence variant was found in thyroid peroxidase of the affected dog [for which a DNA sample was available]."

Clinical features: Soler Arias et al. (2018): "The ITD was recognized by the absence of uptake of technetium-99m in the salivary glands (sg) and goiter observed by scintigraphy. In the same scan, radiopharmaceutical uptake was found in the anterior mediastinum of both [affected] dogs and in the right axillary lymph node in the oldest dog. A follicular thyroid carcinoma was diagnosed by histopathology after thyroidectomy of the older dog. An adenomatous goiter with ectopic thyroid tissue, and degenerative changes in myocardium were the findings after necropsy in the youngest dog."

Breed: Shih-Tzu.

Associated gene: