characteristic radiographic findings of the skeleton such as caudal narrowing of the interpedicular distance , small iliac wing , narrow greater sciatic notch , and metaphyseal flaring of tubular bones are usually observed . average adult height in achondroplasia is , in the caucasian population , between 112 and 136 cm ( mean 124 cm ) for women and 118 - 145 cm ( mean 132 cm ) for men ( 2 ) . this disorder is inherited as an autosomal dominant trait , although the majority of cases are sporadic . at the last decade of the past century , studies have revealed point mutations in the transmembrane domain of the fibroblast growth factor receptor 3 ( fgfr 3 ) gene in achondroplastic heterozygotes and homozygotes ( 3 , 4 ) . the achondroplasia mutation causes increased fgfr3 activity disturbing both proliferation and hypertrophy of the epiphyseal growth plate chondrocytes as well as increasing the pace of osteogenesis ( 5 , 6 ) . growth hormone ( gh ) is an important factor for the growth and differentiation of chondrocytes . trials with gh treatment in achondroplasia have been reported for a long time . already in 1933 , in denmark , a treatment experiment was done using pituitary extracts in a patient with chondrodystrophy ( presumably achondroplasia ) ( 7 ) . at the past nineties , there have been reports describing the beneficial effects of gh therapy in achondroplasia and hypochondroplasia ( 8 - 10 ) , although patients with achondroplasia are considered to have normal gh secretion . in fact , gh has been widely used to treat non - gh - deficient forms of short stature , such as turner s syndrome , intrauterine growth retardation , chronic illness and idiopathic short stature ( 11 - 13 ) . in the study of bouali and latrech ( 2015 ) , a number of treatments for achondroplasia have been compared , including surgical limb lengthening and r - hgh treatment , to future treatments which include the natriuretic peptide c - type ( cnp ) ( 14 ) . in the present study , we evaluated the effectiveness of gh administration on the enhancement of longitudinal bone growth in children with achondroplasia . the patient t. m , 10 years old , was diagnosed with achondroplasia prenatally in the 7 month of gestation . the height of the mother is 163 cm , and of the father is 172 cm . the patient s only sibling is normal . birth weight of the patient was 3150 g , his length was 46 cm , with head circumference of 38 cm . his psychomotor development was normal except for speech difficulties . except the physical features of achondroplasia the computerized tomography ( ct scan ) of the brain did not reveal any abnormalities . his igf1 levels ( 40mg / ml ) and igfbp3 levels ( 1900mg / ml ) were normal . two growth hormone stimulation tests were performed at the age of two years , and the values were within normal range . the genetic testing revealed a mutation of c 1138 g > a in the gene fgfr3 in a heterozygous constellation . we started growth hormone treatment at the age of three years and four months in a dose of 0.06 mg / kg . at start his height was 82.3 cm and weight was 14 kg ( ht sds-2 , 2 ) . growth increased to 10cm / year in the first year of treatment ( ht sds -1 , 1 ) . it decreased during the second year to four cm / year ( ht sds -1 , 7 ) and again increased during the third year to eight cm / year ( ht sds -1 , 3 ) . in the next years the growth was constant ( 6 , 5 cm ; 2 , 3 cm ; 3.5 cm /year ) . at the age of 10 , he is still growing in the third percentile of the normal growth curve ( ht sds -1 , 2 ) . r- hgh administration studies in achondroplasia have been limited , as it was thought initially that gh therapy would not be helpful , given that patients usually do not manifest a hormone deficiency . however , encouraging short - term results of gh treatment in achondroplasia have been reported . although differing age groups , treatment periods , and dosages make comparison between studies difficult , it can be speculated that higher gh doses and younger age of initiation of treatment result in better growth response . the patients were treated daily hgh at a dosage of 1 iu / kg / week . the authors of the study concluded that , hgh treatment resulted in an increased growth rate in some children with achondroplasia . however the increase waned during the second year of treatment , which was not the case in our study . tanaka et al ( 1 ) treated forty two children ( 16 males and 26 females ) with achondroplasia with gh for more than 2 years . gh was administered at a dose of 0.5 iu / kg / week or 1iu / kg / week for at least 2 years . the conclusion of this study was that gh might be beneficial in the treatment of short stature in children with achondroplasia in the first two years of treatment , in accordance to our study . ramaswami et al ( 16 ) described the effects of gh therapy for up to 6 years on stature and body proportions of 35 children with achondroplasia . treatment caused a significant increase in ht sds year to year until year 4 , that was subsequently sustained with no significant further change ( year 5 and 6 versus year 4 ) . age , as in our study , was the most important variable accounting for the first - year response in ht sds and dose of r - hgh did not influence this . the conclusion was that a young age at initiation of therapy prevented the characteristic ht deficit from accumulating . the addition of later surgical leg lengthening could offer the possibility of proportionate adult stature just within the normal range . hertel et al ( 17 ) studied 35 achondroplastic children who received a dosage of either 0.1 iu / kg / day or 0.2 iu / kg / day . gh treatment was interrupted for 12 months after 2 years of treatment in prepubertal patients to study catch - up growth . 6 cm / y for the groups ) increased significantly by 1.9/3.6 cm / y during the first year and by 0.5/1.5 cm / y during the second year . these authors concluded that gh treatment in children with achondroplasia improves height during four years of therapy without adverse effect on trunk - leg disproportion , which data proved to be the same in our case . the data from our case report demonstrated that gh treatment in a prepubertal achondroplastic child increased his growth by 10 cm / year in the first year of follow up . it decreased during the second year to four cm / year ( ht sds -1 . 7 ) and again increased during the third year to eight cm / year ( ht sds -1.3 ) . in the next years the growth was constant ( 6.5 cm ; 2.3 cm ; 3.5 cm / year ) . at the age of 10 , the treatment still continues , because he is growing in the third percentile of the normal growth curve ( ht sds -1.2 ) and he has not yet reached his final height . the growth was satisfactory in the first four years of treatment , although the patient still continued to grow . his young age at start of the treatment was also of importance , which is the conclusion of other authors who performed similar studies . our other patients with achondroplasia who started treatment at an older age had a poor response to gh treatment .
background : achondroplasia is a skeletal dysplasia , the most common cause of rhizomelic dwarfism.case presentation : this is a ten year old boy who was first diagnosed prenatally . he had a mutation c1138g > a in the gene fgfr3 in a heterozygotic constellation . 
 his igf1 and igfbp3 levels were normal . 
 two stimulation tests for growth hormone were performed with values within the reference range . 
 his psychomotor development was adequate for his age except for speech difficulty . 
 he started with recombinant hgh ( r - hgh ) at the age of 3.4 years in a dose of 0.06 mg / kg . 
 his mean height sds ( htsds ) was -2.2.results : the growth increased to 10 cm / year in the first year of therapy ( htsds -1.1 ) . 
 it decreased during the second year to 4 cm ( htsds -1.7 ) and again increased during the third year to 8 cm / year ( htsds1.3 ) . in the next years the growth was constant ( 6.5 , 2.3 , 3.5 cm / year ) . 
 he is still growing in the 3rd percentile of the growth curve ( htsds  1.2 ) under gh treatment . 
 the body disproportion remained the same.conclusion:the growth response on gh treatment was satisfactory in the first 4 years of treatment , and the boy still continued to grow . 
 the young age at the start of treatment was also of importance . 
 our other patients with achondroplasia who started treatment older had a poor response to growth hormone .