X-linked calvarial hyperostosis

MedGen UID:: 1674665
•Concept ID:: C5190611
•: Disease or Syndrome

Synonym:	Isolated hyperostosis of the calvarium
SNOMED CT:	X-linked calvarial hyperostosis (782786001)
Modes of inheritance:	X-linked recessive inheritance MedGen UID: 375779 •Concept ID: C1845977 • Finding Source: Orphanet A mode of inheritance that is observed for recessive traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked recessive disorders manifest in males (who have one copy of the X chromosome and are thus hemizygotes), but generally not in female heterozygotes who have one mutant and one normal allele. See: This record X-linked recessive inheritance (Orphanet)

Monarch Initiative:	MONDO:0010541
OMIM®:	302030
Orphanet:	ORPHA391327

Definition

Calvarial hyperostosis is a benign X-linked disorder that affects only the skull. Symptoms are prominent frontoparietal bones, flat nasal root, short upturned nose, high forehead with ridging of the metopic and sagittal sutures, and lateral frontal prominences. Radiographs of the skull show increased bone thickness at the sagittal suture line and prominent lateral frontal horns. Increased intracranial pressure and cranial nerve entrapment do not occur (summary by Borra et al., 2014). [from OMIM]

Clinical features

From HPO

Calvarial hyperostosis

MedGen UID:: 350147
•Concept ID:: C1863351
•: Finding

Excessive growth of the calvaria.

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Occipital horn

MedGen UID:: 1842007
•Concept ID:: C5782305
•: Anatomical Abnormality

Downward pointing exostoses of the occipital bone situated in the tendinous insertions of the sternocleidomastoid and trapezius muscles.

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High forehead

MedGen UID:: 65991
•Concept ID:: C0239676
•: Finding

An abnormally increased height of the forehead.

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Depressed nasal bridge

MedGen UID:: 373112
•Concept ID:: C1836542
•: Finding

Posterior positioning of the nasal root in relation to the overall facial profile for age.

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Anteverted nares

MedGen UID:: 326648
•Concept ID:: C1840077
•: Finding

Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip).

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