Dwarfism

Etiology

Linear growth in childhood is regulated and influenced by various factors, including genetics, hormones, nutrition, and the environment. These elements play a significant role in cell proliferation and differentiation, as well as in bone development and growth, which are key determinants of height.[2] Understanding the etiology of short stature is crucial for making an accurate diagnosis and determining the most suitable treatment. The causes of short stature can vary widely depending on the extent and nature of growth retardation, as well as accompanying clinical symptoms.

The etiology can generally be categorized into 2 main types: physiological and pathological. Physiological causes, including delay of growth and puberty (CDGP) and familial short stature (FSS), account for approximately 80% to 85% of all cases of short stature. In contrast, pathological causes make up the remaining 15% to 20%.[1]

• Physiological short stature
  • The hallmark is normal growth velocity. These children usually fall within -2 and -3 standard deviation scores (SDS) for the respective population charts. CDGP and FSS are classically described as forms of physiological short stature, as these children otherwise have normal health.
• Constitutional delay of growth and puberty 
  • This is the most prevalent cause of both short stature and delayed puberty, impacting over 2% of adolescents, primarily boys. This condition is characterized by reduced growth velocity before puberty, delayed bone age, and a late onset of the pubertal growth spurt, followed by spontaneous recovery. Ultimately, this often results in an adult height within the genetic target range, though it is typically still below that of their peers.[3]
• Familial Short Stature
  • FSS is a growth variation that aligns with the average height of the parents (determined by calculating the parental target height, which estimates a child's projected adult height based on their parents' heights). Individuals with familial short stature are shorter in stature but have normal growth velocity and bone age. Additionally, there is a family history of short stature, with no other skeletal abnormalities.[4]
• Pathological Short Stature
  • Systemic illnesses
    • Systemic disorders: Other systemic diseases that have a secondary effect on growth are celiac disease, chronic kidney disease, pulmonary/cardiac/gastrointestinal/hepatic/immunologic/metabolic diseases (such as asthma, congenital heart disease, and inflammatory bowel disease), cancer, and glucocorticoid therapy.[1][5]
  • Small for gestational age (SGA) born babies with poor catch-up 
    • Infants born SGA, defined as having length or weight below 2 standard deviations from the mean, are expected to show catch-up growth by 2 to 3 years of age in 85% to 90% of cases.  About 10% to 15% SGA born babies do not catch up by 2–3 years of life and may remain short for life if not intervened.[6] 
  • Malnutrition
    •  In the developing world, it is still the most common cause of short stature (in addition to height, weight is also affected).
• Psychosocial short stature
  • In the western world, where broken families are not uncommon, this should be considered a cause of short stature, as changing the child's environment to a loving and caring one itself will lead to catch-up growth.
• Endocrine disorders
  • Growth hormone deficiency 
    • This is an endocrine disorder characterized by inadequate secretion of growth hormone from the anterior pituitary gland. This condition leads to a progressive reduction in linear growth, resulting in a height that falls more than two standard deviations below the average. The causes of growth hormone deficiency can be either congenital—arising from variations in genes related to the somatotropic pathway, pituitary malformations, or multiple hypopituitarism—or acquired, commonly due to tumors affecting the hypothalamic-pituitary axis, radiotherapy, trauma, or infections. Diagnosing this deficiency requires correlating the patient's clinical history and physical examination with a longitudinal assessment of growth velocity. Additionally, careful interpretation of growth hormone stimulation test results is essential.[7] Cushing syndrome, hypothyroidism, pseudohypoparathyroidism, and poorly treated/untreated precocious puberty are other causes of short stature that are related to and seen in endocrinology. 
• Genetic disorders
  • Short stature can be influenced by various genetic factors. These can be classified into 3 main categories:
    • Monogenic Variants: These involve mutations in single genes that are crucial for growth plate cartilage and the growth hormone-insulin-like growth factor 1 (GH-IGF-1) axis. Notable examples include SHOX (associated with Leri-Weill dyschondrosteosis and Langer mesomelic dysplasia), FGFR3 (linked to achondroplasia and aypochondroplasia), and IGF1 (involved in insulin-like growth factor I deficiency). Additionally, several genetic disorders with multisystem involvement feature short stature as a component; examples include mucopolysaccharidosis, cystic fibrosis, Noonan syndrome, Silver-Russell syndrome, and Prader-Willi syndrome. Please see StatPearls' companion reference "Achondroplasia," and other topics listed here for further information.
    • Oligogenic/polygenic variants: These involve multiple genes, such as NPR2 and ACAN, whose variants interact to reduce height in an additive manner.
    • Chromosomal alterations: An example is Turner syndrome (monosomy of the X chromosome); infertility and short stature are the most notable findings seen in these patients.[1][8][9]
• Idiopathic short stature
  • In idiopathic short stature (ISS), an individual’s height is below 2 standard deviations from the mean for their age, sex, and population, without any evidence of systemic, endocrine, nutritional, or chromosomal causes. Children with ISS typically have a normal birth weight and adequate growth hormone levels. The etiology of ISS is heterogeneous, encompassing currently unidentified causes. As molecular genetics advances, many conditions currently classified as ISS may eventually be recognized as separate entities. This is important for reaching this diagnosis, as it is a Food and Drug Administration-approved indication to treat the child with ISS with recombinant human growth hormone if the child's final predicted height is expected to remain less than 2.25 SDS.[10]

Aside from this classification, short stature can be classified in various ways, including by proportionality. Proportionate short stature is characterized by normal limb and trunk proportions. In contrast, disproportionate short stature is identified when a significant difference between sitting and standing height is observed, typically due to abnormal proportions of body parts.

Another classification separates short stature into primary and secondary growth failure, based on the underlying cause. Primary growth failure occurs when factors directly impair the growth plate’s potential, such as in Turner syndrome or achondroplasia. Secondary growth failure results from external or systemic factors that hinder the growth plate’s ability to reach its full potential, ie, growth hormone deficiency or chronic kidney disease.

Epidemiology

Short stature affects approximately 2% to 3% of the global pediatric population, although its prevalence can vary widely depending on the reference population, the cutoffs used, and environmental factors such as nutrition, socioeconomic status, and ethnicity. Results from a large study of elementary school children in the United States showed that only 555 out of 114,881 children had short stature and poor growth rates. Results from the same study also showed the prevalence of growth hormone deficiency was 1 in 3480.[11]

In regions plagued by malnutrition or poverty, the prevalence of short stature can be considerably higher. Conversely, in developed countries, non-nutritional causes are more prevalent. Recognizing that short stature not only suggests potential underlying health issues but also has psychosocial implications, including diminished self-esteem and an increased risk of bullying, is essential. Moreover, standardizing growth curves for different populations—such as those provided by the World Health Organization or local references—is vital to prevent overdiagnosis, particularly in groups with lower average heights. A careful approach to assessment can help reduce unnecessary interventions by targeting treatable or modifiable causes.[1][12][13]

Pathophysiology

Longitudinal growth of long bones occurs through endochondral ossification in the growth plate, a highly organized cartilaginous structure located between the epiphyses and metaphysis. This plate is divided into distinct functional zones: the quiescent zone containing chondrocyte stem cells; the proliferative zone, where chondrocytes divide under the influence of growth factors, ie, growth hormone; and the hypertrophic zone, where cells enlarge and secrete extracellular matrix proteins before undergoing apoptosis. This coordinated process of proliferation, differentiation, hypertrophy, and programmed cell death enables bone elongation and is regulated by multiple molecular signals, including local growth factors and systemic hormones, which integrate genetic, nutritional, and environmental signals.

Growth physiology is orchestrated by a complex hormonal system that varies with developmental stage. During fetal life, insulin-like growth factors (IGF-1 and IGF-2) and insulin are the primary regulators, whereas in infancy and early childhood, nutrition, in addition to the GH-IGF-1 axis, plays an important role. Growth hormone, produced by the pituitary gland, stimulates both chondrogenesis in the growth plate and hepatic production of IGF-1. This IGF-1 is the chief mediator of growth.

During puberty, sex steroids, particularly estrogens, enhance growth hormone secretion and modulate sensitivity to IGF-1, thereby triggering the pubertal growth spurt. However, paradoxically, these same estrogens eventually induce growth plate fusion, terminating longitudinal growth. Thyroid hormones complement this system by regulating chondrocyte maturation and cartilage matrix synthesis, while factors such as leptin link nutritional status with growth hormone secretion.

Growth can be altered by multiple factors that disrupt normal regulatory processes. Genetic alterations, such as mutations in the SHOX gene that cause Léri-Weill dyschondrosteosis, demonstrate how defects in specific transcription factors can selectively affect the growth of certain bone segments by modulating target genes. Malnutrition compromises growth primarily during the first years of life, reducing IGF-1 levels and altering the expression of growth hormone receptors in the growth plate.

Chronic inflammatory diseases create a catabolic state through proinflammatory cytokines such as tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, which suppress IGF-1 synthesis, inhibit chondrocyte proliferation, and increase apoptosis in the growth plate. Furthermore, there is considerable individual and population variability in growth patterns reflecting complex gene-environment interactions, adaptations to local conditions, and differences in genetic growth potential. Psychosocial short stature results from functional hypofunction of the pituitary and is reversible when the underlying environment is changed.[14][15][16][17]

History and Physical

To effectively evaluate a patient with short stature, it is crucial to obtain a detailed medical history and conduct a thorough physical examination, supported by appropriate laboratory and imaging studies. When assessing a patient with short stature, the first step is to measure their height. Height is measured from the floor to the top of the head while the head is positioned in the Frankfurt horizontal plane, which passes through the orbital floor and the upper margin of the external auditory meatus.

For children older than 2 years, a wall-mounted stadiometer is preferred. For those younger than 2 years, an infantometer is used with the patient lying supine. Between 2 and 3 years, both standing and supine measurements should be taken, as standing height is approximately 1 cm shorter than supine length.

To ensure accuracy, measurements must be taken with shoes and hair accessories removed, the child standing straight with heels, buttocks, scapulae, and occiput against the wall, and the head aligned to the Frankfurt plane. The headplate must rest perpendicular to the wall, and an average of 3 readings is ideal. After obtaining this measurement, it should be compared to established references for age and sex using the growth charts available for the region. This comparison will help determine the patient's standard deviation or percentile ranking.[1]

The height-for-age should be compared to the parental height, which is the average of the parents' heights, plus 6.5 cm for males and minus 6.5 cm for females; this is referred to as mid-parental height. This measurement reflects the child's genetic potential and helps avoid overdiagnosis of short stature in an otherwise healthy child. Additionally, a longitudinal growth analysis should be conducted, measuring height velocity (in cm/year or standard deviation) against age-specific references. This analysis is performed by comparing height and age at 2 successive visits, ideally spaced 6 to 12 months apart.

The clinical history should begin with inquiries about the pre- and perinatal periods. Asking about any complications during pregnancy, such as infections, preeclampsia, and intrauterine growth restriction, is essential, as these conditions can lead to reduced fetal growth. Information regarding gestational age at birth, length, and birth weight is also crucial. For instance, a history of intrauterine growth restriction is significant because up to 15% of affected individuals fail to achieve "catch-up" growth in height later in life.[18]

Additionally, the clinical history should include details on neurodevelopmental milestones, dietary habits, and any chronic medication use that may affect growth patterns, such as steroids. At this stage, it is also important to consider family history as a significant factor. Investigating parental consanguinity is essential, as it may indicate an increased risk of genetic disease.[18][19]

In addition to determining height and its relation to population reference patterns and genetic potential, other measurements should be taken to identify the cause of this condition. Measuring body segments (both upper and lower), wingspan, weight-for-age, and head circumference (under 5 children) is vital. Proportions are assessed using the upper-to-lower segment (US:LS) ratio, calculated by subtracting the lower segment (upper border of pubic symphysis to the floor) from total height.

At birth, the US: LS is approximately 1.7:1, which normalizes to 1:1 by 7 years. An increased US:LS ratio may point toward hypothyroidism, achondroplasia, or rickets, while a decreased ratio may indicate vertebral anomalies or spondyloepiphyseal dysplasia.[18][20] Facial dysmorphisms linked to specific genetic syndromes should be evaluated. Additionally, sexual maturation should be assessed using the Tanner scale.[20]

Evaluation

Laboratory Tests

For children with heights between -2 and -3 SDS, physiological short stature should be considered more likely, taking into account family history and midparental height. 

Initial screening workup 

In case of a height standard deviation score of less than -2, no familial/CDGP pattern:

• Complete blood count: Screen for hematological diseases, such as anemia.
• Liver function: Screen alanine aminotransferase, aspartate aminotransferase, and albumin.
• Renal function: Check serum creatinine and electrolytes (Na+, K+); obtain venous blood gas (for acidosis, especially in younger children).
• Thyroid function: Screen free T4 (FT4) and thyroid-stimulating hormone.
• Celiac screening: This includes immunoglobulin A (IgA) type of anti-tissue transglutaminase (anti-ttG IgA), serum IgA, and, in selected cases, anti-endomysial antibodies.
• Calcium profile: Check serum calcium, phosphorus, and alkaline phosphatase (screen for rickets/metabolic bone disease).
• Perform a routine urine and stool examination for casts and parasitic cysts, respectively.

Targeted/Second-Line Tests 

Based on screening results or clinical clues:

• Fecal calprotectin: If the body mass index standard deviation score is less than -1, and if there is a suspicion of irritable bowel disease.
• Karyotype:
  • Indication: All girls with unexplained short stature (even without Turner syndrome features).
• Perform urinary free cortisol or cortisol suppression tests (Cushing syndrome), vitamin D, parathyroid hormone, calcium (pseudohypoparathyroidism), follicle-stimulating hormone/lutenizing hormone (Turner syndrome/Prader-Willi syndrome).

Radiographic Tests

• X-ray nondominant hand/wrist for bone age assessment:
  • Assess growth potential; differentiate CDGP (mild delay) vs endocrine causes (severe delay) or familial short stature (bone age appropriate for chronological age).
• Perform spine/limb x-rays if disproportion or dysmorphism:
  • Assess for skeletal dysplasia.

GH-IGF1 Axis Evaluation

Only after excluding other causes:

• Growth hormone stimulation test:
  • Perform with clonidine, glucagon, or an insulin tolerance test.
  • Diagnosis: Peak growth hormone <7 ng/mL
• In peripubertal children, the growth hormone stimulation test should be performed after priming with sex steroids. 
• Neuroimaging (eg, MRI): when confirmed GH deficiency (to assess pituitary structure). [1][2][19][2][20]
• See the StatPearls chapter on short stature for more details.[Short Stature - StatPearls - NCBI Bookshelf]

Treatment / Management

Treatment of short stature should be guided by the underlying cause. For most systemic illnesses, infections, or chronic nutrient deficiencies, treating the underlying cause will lead to catch-up growth. In cases of physiological causes, treatment can be offered on an individual basis if the child or family has significant psychological distress arising from short stature.

Treatment with recombinant human growth hormone (rhGH) represents the primary therapeutic intervention for short stature in children. The Food and Drug Administration-approved indications for pediatric use include growth hormone deficiency, Turner syndrome, Prader-Willi syndrome, Noonan syndrome, chronic renal failure, children born small for gestational age without catch-up growth, idiopathic short stature, and SHOX gene defect. Growth hormone therapy is aimed at both replacing hormone deficiency when present and promoting growth in conditions where short stature is not primarily due to endogenous growth hormone deficiency.[21](B3)

rhGH dosage should be individualized based on the specific diagnosis and patient response. For GH deficiency, the Pediatric Endocrine Society recommends doses of 22 to 35 mcg/kg/day, as these patients require lower doses to achieve catch-up growth and normal adult height. The Growth Hormone Research Society suggests using lower doses for severe growth hormone deficiency, as patients respond very well to these lower doses (17–35 mcg/kg/day). These guidelines are for initiation only; doses should be individualized thereafter based on auxology and IGF-1 levels. For other indications unrelated to growth hormone deficiency, such as idiopathic short stature or Turner syndrome, doses may need to be higher, typically towards the upper limit of the approved range.[19][22](B3)

Dose adjustment should be based primarily on growth response, with assessment of growth velocity and change in the standard deviation of height every 6 to 12 months. Serum IGF-I levels can provide additional information on treatment efficacy, adherence, and, theoretically, safety. For patients with growth hormone deficiency, the IGF-I goal should be close to 0 SDS, whereas for conditions without growth hormone deficiency, such as idiopathic short stature or Turner syndrome, IGF-I levels of approximately +1 SDS or higher are usual. When consecutive IGF-I levels are above +2 SDS, consideration should be given to reducing the rhGH dose to achieve long-term IGF-I levels within the normal range, unless IGF-I insensitivity is likely.[19](B3)

Treatment should be continued until the child reaches their genetic growth potential, reaches a socially acceptable height, or growth velocity decreases to 2 cm/year or less, as observed over at least 6 months. rhGH therapy is effective in increasing final adult height: children with GH deficiency may experience changes in the mean height score between 1.8 and 3.5 standard deviations, whereas in idiopathic short stature, the average increase is approximately 1.2 to 2.8 inches (3.0 to 7.1 cm). Predictors of better response include younger age at treatment initiation, delayed skeletal maturation, or taller parents. Suboptimal treatment response requires assessment of adherence, injection techniques, and consideration of other etiologies of growth failure, including celiac disease, inflammatory bowel disease, hypothyroidism, inadequate nutrition, or growth-altering medications.[22][23]

Beyond recombinant human growth hormone, other pharmacologic therapies have been developed to address specific causes of growth failure. Recombinant human insulin-like growth factor-1, or mecasermin, is used in children with growth hormone resistance, such as in Laron syndrome, and in those with genetic defects affecting the GH–IGF–1 axis, including primary IGF-1 deficiency and pregnancy-associated plasma protein A2 deficiency. Treatment typically involves subcutaneous injections every 12 hours. Since IGF-1 therapy can induce hypoglycemia, precautions must be taken during administration.[24]

Aromatase inhibitors, which block the conversion of androgens to estrogens, specifically androstenedione to estrone and testosterone to estradiol, are used to delay epiphyseal fusion and prolong the growth window in selected children, primarily boys. Gonadotropin-releasing hormone analogs are employed to delay or halt puberty in children with precocious puberty or short stature at the onset of puberty. These therapies may improve final height outcomes when used alone or in combination with human growth hormone.[25][26][27] (A1)

Vosoritide, a recombinant C-type natriuretic peptide analog, has shown sustained improvement in growth velocity for up to 42 months in children with achondroplasia.[28] For individuals experiencing psychological distress due to short stature, psychosocial counseling is essential to help them develop coping strategies and improve their quality of life. For the last few years, different weekly forms of growth hormone have been available in different parts of the world. See StatPearls's chapter on short stature for more details.[Short Stature - StatPearls - NCBI Bookshelf](A1)

Differential Diagnosis

The differential diagnoses for dwarfism include the following:

• Variants of normality: Familial short stature and constitutional delay in growth and puberty.
• Hormonal deficiency and endocrinopathies: Growth hormone deficiency, congenital or acquired (eg, after radiotherapy, pituitary tumors), insensitivity or resistance to growth hormone, primary or secondary IGF-I deficiency, congenital or acquired hypothyroidism, hypogonadotropic hypogonadism, Cushing syndrome (endogenous or due to exogenous glucocorticoids)
• Genetic syndromes: Turner syndrome, Noonan syndrome, imprinting syndromes (Silver-Russell, Prader-Willi), pseudohypoparathyroidism, mucopolysaccharidosis, or other inborn errors of metabolism
• Chronic systemic diseases: Chronic kidney failure, inflammatory bowel disease (Crohn disease, ulcerative colitis), severe congenital heart disease, celiac disease, chronic respiratory diseases (cystic fibrosis, severe asthma)
• Malnutrition and environmental factors: Protein malnutrition, micronutritional malnutrition (vitamin A, D, and zinc deficiencies), and psychosocial issues
• Skeletal dysplasias and local bone disorders: Skeletal dysplasia (achondroplasia, metaphyseal dysplasia), neonatal hypophosphatasia
• Other causes: Small for gestational age without catch-up growth, sequelae of infection or chronic inflammation (tuberculosis, HIV)

Treatment Planning

Treatment planning with growth hormone in children with short stature should be based on clearly established criteria and a comprehensive hormonal and genetic evaluation. First, the diagnosis of growth hormone deficiency will be confirmed by at least 2 stimulation tests; once diagnosed, the recommended initial dose may vary with weight and should be adjusted later based on growth rate and serum IGF-1 levels. Individualizing the dose to maintain IGF-1 within the physiological range is essential. During follow-up, height will be monitored quarterly, in addition to monitoring for potential adverse effects, including intracranial hypertension and metabolic abnormalities. Finally, the optimal duration of treatment will depend on the timing of epiphyseal fusion and generally be discontinued when the growth rate is less than 2 cm/year or the target height is reached.

Prognosis

The prognosis for children with short stature depends on the etiology and timing of treatment initiation. In children with organic or genetic growth hormone deficiency, the response to growth hormone therapy is usually more favorable, with more pronounced increases in growth velocity and adult height than in idiopathic cases, especially when treatment is initiated before puberty, and the dose is adjusted based on IGF-1 levels and growth velocity. However, determining growth hormone deficiency with stimulation tests has limited sensitivity and specificity, so integrating clinical, biochemical, and pituitary neuroimaging criteria is recommended for a more comprehensive assessment.[22]

In non–growth hormone deficiency conditions treated by rhGH, the prognosis remains relatively modest. In Turner syndrome, the prognosis improves when growth hormone therapy is combined with adjuvants and extended until before epiphyseal fusion, optimizing height gain and reducing the risk of complications. In any form of short stature, early detection and a multidisciplinary approach—including nutritional support, monitoring for adverse effects, and psychosocial support—are essential to maximize growth potential and minimize long-term consequences.[21]

Complications

Short stature may be indicative of chronic hormonal or nutritional deficiencies that lead to altered bone metabolism, with lower mineral density and a greater predisposition to fractures, as well as altered lipid and carbohydrate metabolism, predisposing to insulin resistance and metabolic syndrome later in life. Similarly, an elevated risk of cardiovascular events has been observed in patients with growth hormone deficiency. Beyond the physical consequences, short stature can have significant psychosocial repercussions.

Although clinical evidence suggests that not all children who are short experience impaired emotional well-being, many adolescents report feeling stigmatized or experiencing low self-esteem because of their height. This perception can influence the development of social interactions, reduce participation in sports activities, and, in some cases, motivate the search for additional treatments, including sex hormone analogues or growth hormone therapies for unapproved indications. The approach to short stature must consider both medical risks and psychological needs to provide comprehensive care for the affected child or adolescent.