Microcephaly is a rare, neurological disorder in which the circumference of the head is smaller than the average for the age and gender of the infant. Microcephaly may be congenital or it may develop in the first few years of life.

This disorder may be caused by a wide variety of conditions that effect the growth of brain. It is often associated with chromosomal abnormality.

Infants with microcephaly may be born with a normal or reduced head size. The head fails to grow while the face continues to develop at a normal rate, producing a child with a small head, a large face, and a loose, often wrinkled scalp. As the child grows the smallness of the head becomes more obvious. Whole body is also underdeveloped. Motor functions and speech are delayed. Motor ability may vary, and it may be clumsy movements or even quadriplegia (paralysis of both upper and lower limbs).Hyperactivity and mental retardation are common. Convulsions may also occur.

The is no specific treatment in such cases. Treatment is symptomatic and supportive. Life expectancy is low and the prognosis for normal brain function is poor.

Genetic

1. Autosomal Recessive (Familial)
2.  Autosomal Dominant
3.  Syndromes

Syndromes

• Aicardi Syndrome
• Beckwith-Wiedemann Syndrome
• Bloom Syndrome
• Cohen Syndrome
• Cornelia de Lange
• Cri-du-chat (5p-)
• Dubowitz Syndrome
• Rubinstein-Taybi Syndrome
• Smith-Lemli-Opitz Syndrome
• Trisomy 21
• Trisomy 18
• Trisomy 13
• Xeroderma Pigmentosum

Non Genetic

1. Congenital CNS Anomalies

• Agenesis of the Cerebellar Vermis
• Agenesis of the Corpus Callosum
• Craniosynostosis
• Encephalocele
• Holoprosencephaly
• Lissencephaly
• Macrogyria
• Porencephaly
• Schizencephaly

2. Congenital Infections

• CMV
• Rubella
• Toxoplasmosis
• Varicella

3. Drugs

• Alcohol
• Aminopterin
• Dilantin
• Methyl Mercury

4. Hypoxic-Ischemic Encephalopathy

5. Infections

• Encephalitis
• Meningitis

6. Metabolic

• Maternal Diabetes Mellitus
• Maternal PKU
• Inborn Errors of Metabolism
• Neuronal Ceroid Lipofuscinoses

7. Others

• Radiation
• Hyperthermia