Hypotonia - failure to thrive - microcephaly

Failure to thrive (FTT) indicates insufficient weight gain or inappropriate weight loss in pediatric patients unless the term is more precisely defined. In children, it is usually defined in terms of weight, and can be evaluated either by a low weight for the child's age, or by a low rate of increase in the weight.The term "failure to thrive" has been used vaguely and in different contexts to refer to different issues in pediatric growth. [Source: Wikipedia ]

Leukotriene C4 synthase deficiency
LTC4 synthase deficiency
OrphaNet reference
Hypotonia - failure to thrive - microcephaly 
May Cause
Failure to thrive