Biotinidase deficiency is an inherited metabolic disorder of biotin (vitamin B) recycling that leads to multiple carboxylase deficiencies.

Symptoms of untreated biotinidase deficiency may appear at any time from 1 week to10 years of age. The most common early symptoms include seizure activity of various types (myoclonic, grand mal, and focal or infantile spasms) and hypotonia. Other early symptoms include breathing problems (tachypnea, hyperventilation, stridor, apnea), skin rashes and alopecia. Later developmental delays, speech problems, ataxia, and vision and hearing problems may occur. Less frequent findings include feeding difficulties, vomiting/diarrhea, fungal infections, hepatomegaly and splenomegaly.

This disorder is inherited in an autosomal recessive pattern. As an autosomal recessive disorder, the parents of a child with biotinidase deficiency are unaffected, healthy carriers of the condition and have one normal gene and one abnormal gene. With each pregnancy, carrier parents have a 25 percent chance of having a child with two copies of the abnormal gene, which results in biotinidase deficiency. Carrier parents have a 50 percent chance of having a child who is an unaffected carrier and a 25 percent chance of having an unaffected, non-carrier child. These risks hold true for each pregnancy. All siblings of infants diagnosed with biotinidase deficiency should be tested; genetic counseling services should be offered to the family.

Disorders Detected By Other Technologies

1.  Galactosemia
2.  Congenital Hypothyroidism
3.  Congenital Adrenal Hyperplasia
4.  G6PD
5.  Cystic Fibrosis
6.  Biotinidase
7.  Hemoglobinopathies