Amish lethal microcephaly

Amish lethal microcephaly is a rare inherited disorder present from birth. It is marked by severe microcephaly, a very small head, together with an underdeveloped brain and a small chin. Affected babies become irritable at about the second or third month of life, have seizures and have trouble controlling body temperature. Their urine contains high levels of alpha-ketoglutaric acid, and some also have an enlarged liver. Infants with the condition typically die at around six months of age. The disorder takes its name from the Old Order Amish communities of Pennsylvania, where it was discovered and where about one baby in 500 is affected and roughly one person in eleven carries the recessive mutation without being ill. No cases have been found outside this population. It is caused by mutations in the SLC25A19 gene on chromosome 17 and follows an autosomal recessive pattern of inheritance.