Hypoglossia With Situs Inversus

Description

Hypoglossia with situs inversus is a very rare congenital condition that likely represents a developmental field defect. Only sporadic cases have been reported (Faqeih et al., 2008).

Hypoglossia is part of a group of malformation syndromes collectively termed 'oromandibular limb hypogenesis syndromes,' that usually include limb defects. Hall (1971) provided a classification system (see 103300). See also agnathia with holoprosencephaly (202650), which shows hypoglossia and situs inversus in addition to severe neurodevelopmental defects.

Clinical Features

Hypoglossia with Situs Inversus

Watkin (1925) reported a girl with congenital absence of the anterior two-thirds of the tongue, small mandible, absence of several teeth, and hypertrophy of the sublingual glands. The latter appeared to have made speech possible. She also had complete situs inversus, with a right-sided heart and left-sided liver.

Hussels (1971) reported a 10-year-old girl with microglossia, hypodontia, micrognathia, and situs inversus. At birth, she was noted to have a very small chin and tongue, which caused difficulty in feeding. She developed normally but had disturbed speech. She also had bilateral, primarily conductive, mild hearing loss. Fingers and toes were normal. She had 6 healthy older sibs, and there was no family history of similar disorders.

Oulis and Thornton (1982) reported a 14-month-old black male infant with an underdeveloped mandible, severe hypoglossia, low-set ears, and a sloping forehead. He had complete situs inversus with dextrocardia and asplenia. He had feeding and respiratory problems resulting from his small tongue. Physical examination showed absence of the anterior two-thirds of the tongue, high narrow palate, hypodontia, and hypertrophy of the sublingual glands. During pregnancy, the mother had pneumonia treated with antibiotics and underwent chest radiographic studies. There was no relevant family history.

Dunham and Austin (1990) reported a black newborn with micrognathia, lingual agenesis, and situs inversus. He presented at birth with upper airway obstruction, cyanosis, and bradycardia. The anterior mandible was short, narrow, and wedge-shaped. He had an arched palate with thickening of the maxillary alveolar ridge. Radiographic studies showed complete situs inversus. He had 1 normal sib, and there was no family history. The case fit into type I of the classification of oromandibular limb hypogenesis syndromes delineated by Hall (1971): hypoglossia without associated limb defects.

Jang et al. (1997) reported congenital aglossia, an underdeveloped mandible, and situs inversus totalis in a 10-day-old girl who presented with feeding difficulties and weight loss. There were no limb anomalies and no family history of the disorder.

Amor and Craig (2001) described a Vietnamese girl with microstomia, hypoglossia, micrognathia, and situs inversus. The main complications were airway compromise and feeding difficulties requiring tracheostomy and gastrostomy. There were no limb defects. Amor and Craig (2001) postulated that situs inversus with hypoglossia may represent a mild form of agnathia-holoprosencephaly, but also noted that it may be a variant of hypoglossia-hypodactyly without limb defects. In human embryogenesis, the tongue develops near the end of the fourth embryonic week, with the anterior two-thirds arising from the first branchial arch and the posterior third from the third branchial arch. Left-right asymmetry becomes apparent during the fourth embryonic week, although the process begins earlier. The disorder is likely a developmental field defect.

Faqeih et al. (2008) reported a 2-year-old male with small oral cavity and tongue, hypoplastic mandible, and situs inversus totalis. He had prominent lower alveolar ridges and low-set ears. He had gross motor delay and underdeveloped speech.

Isolated Hypoglossia

Weingarten et al. (1993) reported a white male infant with marked micrognathia and complete absence of the anterior two-thirds of the tongue with a rudimentary posterior tongue. There were no other anomalies. The child learned how to eat and underwent speech therapy. The phenotype was consistent with type I of Hall's classification.

Thorp et al. (2003) described severe microglossia and micrognathia in 5 unrelated South African patients. All had feeding and respiratory difficulties, often requiring a nasogastric feeding tube or tracheostomy at some point. One patient also had extraarticular temporomandibular joint ankylosis. None had limb anomalies or situs inversus. Thorp et al. (2003) classified all affected children as having type V of Hall's classification: the Pierre-Robin syndrome (261800), which is characterized by micrognathia and posterior displacement of the tongue resulting in feeding and respiratory problems.