Gracile Bone Dysplasia

Clinical Characteristics
Ocular Features: 

The eyes have been described as small.  Aniridia may be present.

Systemic Features: 

This is a usually fatal form of skeletal dysplasia with splenic and ocular features as well.  In utero death is not uncommon while newborns may not survive the neonatal period.  The face has been described as dysmorphic with a high forehead, flat nasal bridge, a cloverleaf-shaped skull, and hypoplastic cranial bones with premature suture closure.  The long bones are dysplastic as well with thinned diaphyses (sometimes fractured in utero), growth plate disorganization, excessive remodeling, and signs of arrested growth.  The ribs share in the dysplasia but pulmonary hypoplasia has also been described.  Most individuals have short limbs.

The spleen can be hypoplastic or aplastic and ascites has been noted in several infants.  Failure to thrive is common and seizures have been reported.  Males may have micropenis and hypospadias while females have been described with labial fusion.  

Low parathyroid hormone levels and hypocalcemia has been reported in most individuals.

Genetics

Heterozygous mutations in the FAM111A gene (11q12.1) have been associated with this disorder.  The functional role of FAM111A products is unknown but likely play a role in calcium metabolism, parathyroid hormone secretion, and osseous development.

Mutations in the same gene can be responsible for the allelic autosomal dominant Kenny-Caffey syndrome (127000) with some similar features.

Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

FAM111A mutations result in hypoparathyroidism and impaired skeletal development

Unger S, Gorna MW, Le Bechec A, Do Vale-Pereira S, Bedeschi MF, Geiberger S, Grigelioniene G, Horemuzova E, Lalatta F, Lausch E, Magnani C, Nampoothiri S, Nishimura G, Petrella D, Rojas-Ringeling F, Utsunomiya A, Zabel B, Pradervand S, Harshman K, Campos-Xavier B, Bonafe L, Superti-Furga G, Stevenson B, Superti-Furga A. FAM111A mutations result in hypoparathyroidism and impaired skeletal development. Am J Hum Genet. 2013 Jun 6;92(6):990-5.

PubMed ID: 
23684011

References

Elliott AM, Wilcox WR, Spear GS, Field FM, Steffensen TS, Friedman BD, Rimoin DL, Lachman RS. Osteocraniostenosis-hypomineralized skull with gracile long bones and splenic hypoplasia. Four new cases with distinctive chondro-osseous morphology. Am J Med Genet A. 2006 Jul 15;140(14):1553-63.

PubMedID: 16770805

Unger S, Gorna MW, Le Bechec A, Do Vale-Pereira S, Bedeschi MF, Geiberger S, Grigelioniene G, Horemuzova E, Lalatta F, Lausch E, Magnani C, Nampoothiri S, Nishimura G, Petrella D, Rojas-Ringeling F, Utsunomiya A, Zabel B, Pradervand S, Harshman K, Campos-Xavier B, Bonafe L, Superti-Furga G, Stevenson B, Superti-Furga A. FAM111A mutations result in hypoparathyroidism and impaired skeletal development. Am J Hum Genet. 2013 Jun 6;92(6):990-5.

PubMedID: 23684011