Compound Heterozygous Variants in FAM111A Cause Autosomal Recessive Kenny-Caffey Syndrome Type 2

Kenny-Caffey syndrome (KCS) is a rare autosomal recessive (AR) /dominant disease characterized by hypoparathyroidism, skeletal dysplasia, dwarfism, and dysmorphism. FAM111A or TBCE gene mutations are responsible for this syndrome. Osteocraniostenosis (OCS) is a lethal syndrome with similar features to KCS, and it can be a severe form of KCS type 2 which results from the FAM111A gene mutation. The FAM111A mutation is generally characterized by the autosomal dominant transition. We present a male case having compound heterozygous variants (c. 976T>A and c. 1714₁716del) in the FAM111A gene with an AR inheritance pattern. Hypocalcemia developed on the second day of life. The patient and his older sister had a dysmorphic face, skeletal dysplasia, and they were diagnosed with hypoparathyroidism. Both siblings died due to septicemia. He is the first reported patient with the FAM111A mutation in Turkey. The phenotype of the patient is compatible with OCS, and the detected variants may explain the disease genetically.