A previously healthy, Hispanic, 3-month-old male infant comes in to clinic with a complaint of a possible seizure. His mother was attempting to feed him his formula via a bottle, which he used to eat well but lately has been having trouble taking in, when she noticed a twitching of his extremities and eye rolling. The episode lasted about 1 minute. The mother is scared because there is a history of males in her family with seizures and developmental delay.
Upon exam, you note an alert infant who has truncal hypotonia with poor head control as compared to your exam a month earlier. He has a full head of hair, but it is coarse in texture and shorter and paler than his mother’s and sibling’s hair. He has a pectus excavatum and umbilical hernia, and his face has developed more than before with saggy cheeks and large ears. He has a high-arched palate. He seems to have loose skin on his neck and axilla. What is the most likely diagnosis?
B. Acrodermatitis enteropathica
Hemochromatosis is caused by mutations in proteins that govern iron homeostasis, hepcidin, and ferroportin. Iron overload caused by hemochromatosis can be managed with monthly phlebotomies to remove iron. Hemochromatosis presents with enlarged liver; cirrhosis of the liver, which causes increased bilirubin and jaundice; weakness; edema; and enlarged heart.
Acrodermatitis enteropathica is caused by low zinc levels and presents with acral skin lesions, alopecia, dermatitis, diarrhea, irritability, and failure to thrive. The diagnosis is made on the basis of a low serum zinc level (< 60 μg/dL), although symptomatic infants with normal or only slightly decreased serum zinc levels have been reported.
Menkes disease is an X-linked recessive disorder of copper transport caused by diverse mutations in a copper-transporting ATPase, ATP7A (OMIM no. 309400). Menkes disease typically presents in males at 2 to 3 months of age with loss of previously obtained developmental milestones and the onset of hypotonia, seizures, and failure to thrive. Characteristic physical changes of the hair and facies in conjunction with typical neurologic findings often suggest the diagnosis. Scalp hair in classically affected infants is short, sparse, coarse, and twisted. Light microscopy of the hair will illustrate pathognomonic pili torti (180-degree twisting of the hair shaft) and often other abnormalities, including trichoclasis (transverse fracture of the hair shaft) and trichoptilosis (longitudinal splitting of the shaft). The hair tends to be lightly pigmented and may show unusual colors such as white, silver, or gray, but ...