Cartilage-hair hypoplasia syndrome (CHH) is a rare autosomal recessive condition characterized by metaphyseal chondrodysplasia and characteristic hair, together with a myriad of other symptoms, being most common immunodeficiency and gastrointestinal complications. A 15-year-old Mexican male initially diagnosed with Hirschsprung disease and posterior immunodeficiency, presents to our department for genetic and complementary evaluation for suspected CHH. Physical, biochemical, and genetic studies confirmed CHH together with IGF-1 deficiency. For this reason, we propose IGF-1 replacement therapy for its well-known actions on hematopoiesis, immune function and maturation, and metabolism. Ó 2016 Wiley Periodicals, Inc.Key words: cartilage-hair hypoplasia; IGF-1; RMRP gene; GHR
INTRODUCTIONCartilage-hair hypoplasia syndrome (CHH) is a rare autosomal recessive condition that was originally described by McKusik in 1964 in Amish children. In this population, it accounts for one in 1,300 newborns [McKusick et al., 1965], while in the Finnish population it accounts for one in 23,000 newborns [M€ akitie and Kaitila, 1993]. Outside those populations it is extremely rare, with no incidence data available [M€ akitie and Kaitila, 1993]. The genetic locus for this disease falls within the RNA Component Of Mitochondrial RNA Processing Endoribonuclease (RMRP) gene, localized in chromosome 9p12, which codes for the RMRP, believed to be required for cell cycle, mtDNA replication and rRNA processing [Ridanp€ a€ a et al., 2001;Hermanns et al., 2005;Thiel et al., 2005;Martin and Li, 2007]. The RMRP RNA product associates with at least seven proteins whose interactions and roles remain to be discovered [Welting et al., 2004].The hallmark of this condition is a metaphyseal chondrodysplasia and characteristic hair (fine, sparse with scalp, blond eyelashes-93%), with other several signs and symptoms including short stature and skeletal dysplasia (100%) with varum deformation of lower extremities, hypoplastic anemia during childhood (79%), immunodeficiency (during childhood they may present different recurrent infections secondary to an immunodeficiency that may be humoral, B-cell or T-cell, or combined-56%) [Pierce and Polmar, 1982;M€ akitie et al., 1998, 2000bBaradaran-Heravi et al., 2008] with higher risk of malignancies, skin and nails abnormalities, gastrointestinal diseases (such as Hirschsprung disease [HD], malabsorption, anal stenosis and esophageal atresia-18%) [M€ akitie et al., 2002, 2000a], and failure to thrive [M€ akitie et al., 1992;Glass and Tifft, 1999;Riley et al., 2015]. The growth failure is progressive, owing, partly, to a weak or absent pubertal growth spurt; pubertal maturation is normal; testicular size is abnormal in some patients with normal serum concentrations of testosterone, inhibin B and gonadotropins [M€ akitie et al., 2001].These patients are symptomatic since birth, showing short-limb dwarfism and short puffy hands, with normal head circumference [Giedion, 1998]. The final adult heights range from 100.7 t...