Identification of a novel homozygous ALX4 mutation in two unrelated patients with frontonasal dysplasia type‐2

We report two unrelated boys with frontonasal dysplasias type‐2 (FND‐2) who shared an identical novel homozygous ALX4 mutation c.291delG (p.Q98Sfs*83). Both patients presented with a large skull defect but one had bilateral parietal meningocele‐like cysts that lie along with the bony defect and incr...

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Bibliographic Details
Published in:American journal of medical genetics. Part A 2018-05, Vol.176 (5), p.1190-1194
Main Authors: El‐Ruby, Mona, El‐Din Fayez, Alaa, El‐Dessouky, Sara H., Aglan, Mona S., Mazen, Inas, Ismail, Nora, Afifi, Hanan H., Eid, Maha M., Mostafa, Mostafa I., Mehrez, Mennat I., Khalil, Yasmin, Zaki, Maha S., Gaber, Khaled R., Abdel‐Hamid, Mohamed S., Abdel‐Salam, Ghada M. H.
Format: Article
Language:English
Subjects:
Alopecia
ALX4 dosage effect
Cerebellum
Corpus callosum
Cysts
Dysplasia
frontonasal dysplasia
Genetic counseling
Gonads
impalpable gonads
Meninges
meningocele
Mutation
Neuroimaging
Occipital lobe
parietal foramina
Scalp
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Summary:We report two unrelated boys with frontonasal dysplasias type‐2 (FND‐2) who shared an identical novel homozygous ALX4 mutation c.291delG (p.Q98Sfs*83). Both patients presented with a large skull defect but one had bilateral parietal meningocele‐like cysts that lie along with the bony defect and increased in size with age. Scalp alopecia, hypertelorism, and clefted alae nasi were also detected in both of them. Furthermore, impalpable gonads were noted, being unilateral in one and bilateral in the other. Neuroimaging showed small dysplastic occipital lobes with dysgyria and midline subarachnoid cyst. Additional dysplastic corpus callosum and small cerebellar vermis were observed in one patient. Parietal foramina were noted in the parents of one patient. Our findings highlight the dosage effect of ALX4 and underscore the challenges of prenatal genetic counseling. Further, the indirect role of ALX4 in the development of the occipital lobe and posterior fossa is discussed.
ISSN:1552-4825
1552-4833
DOI:10.1002/ajmg.a.38655