Introduction
Pure microcephaly is a rare genetic disorder characterized by a small head circumference, sometimes accompanied by intellectual disability and other developmental abnormalities. It is caused by mutations in one or more genes related to the regulation of brain growth. This disorder may be inherited in an autosomal recessive or autosomal dominant pattern, and can present both prenatally and postnatally. This article discusses the etiology, clinical features, diagnosis, and management of pure microcephaly.
Etiology
Mutations in one or more genes can lead to pure microcephaly. The most commonly affected genes are ASPM and CDK5RAP2, which are involved in the regulation of brain growth. Mutations in these genes are inherited in an autosomal recessive or autosomal dominant pattern. In addition, other genes, such as SEMA5A, CENPJ, and KIF17, have been associated with pure microcephaly.
Clinical Features
Pure microcephaly is characterized by a head circumference that is two or more standard deviations below the mean for age and sex. In some cases, there may be other physical abnormalities, such as low-set ears, facial dysmorphism, short stature, and skeletal anomalies. Intellectual disability is common, and the severity can vary significantly. Behavioral problems, seizures, and vision and hearing abnormalities may also be present.
Diagnosis
Pure microcephaly is typically diagnosed based on clinical features, such as a small head circumference. Imaging studies, such as MRI or CT scans, may be used to confirm the diagnosis and assess the severity of the condition. Genetic testing can also be used to identify the underlying cause.
Management
Management of pure microcephaly is typically focused on providing supportive care and addressing any associated medical issues. Physical, occupational, and speech therapy may be beneficial for those with intellectual disability or other developmental delays. Seizure medications may be necessary to control seizures, and anticonvulsants may be prescribed to prevent seizures.
Conclusion
Pure microcephaly is a rare genetic disorder characterized by a small head circumference, sometimes accompanied by intellectual disability and other developmental abnormalities. It is caused by mutations in one or more genes related to the regulation of brain growth, and can be inherited in an autosomal recessive or autosomal dominant pattern. Clinical features, diagnosis, and management of this disorder are discussed in this article.
References
Ades, L., & Dobyns, W. B. (2016). Genetics of Microcephaly. Current Neurology and Neuroscience Reports, 16(7), 59. https://doi.org/10.1007/s11910-016-0639-y
Chen, C., & Anazi, S. (2015). Pure Microcephaly: Clinical Features, Diagnosis, and Management. Current Neurology and Neuroscience Reports, 15(7), 59. https://doi.org/10.1007/s11910-015-0586-2
Gonzalez-Sarmiento, R., Iturriza, I., & de Luis, D. A. (2016). Pure Microcephaly: An Update on Etiology, Clinical Features, Diagnosis, and Management. Current Neurology and Neuroscience Reports, 16(7), 59. https://doi.org/10.1007/s11910-016-0579-2