by hyperthyroidism or other causes) (see Chapter 21). Psycho-psychosocial environment, GH physiology normalizes, and logical difficulties also can affect growth, as in psychosocial growth occurs. or deprivation dwarfism, in which the child develops func-The common condition known as constitutional delay in tional temporary GH deficiency and poor growth as a result growth or puberty or both is considered a variation of normal of psychological abuse; when placed in a different, healthier growth, caused by a reduced tempo, or cadence, of physiologic
Figure 173-1 Patterns of linear growth. Normal growth percentiles (5th, 50th, and 95th) are shown along with typical growth curves for A, Constitutional delay of growth and adolescence (short stature with normal growth rate for bone age, delayed pubertal growth spurt, and eventual achievement of normal adult stature). B, Familial short stature (short stature in childhood and as an adult). C, Acquired pathologic growth failure (e.g., acquired untreated primary hypothyroidism) (see Chapter 5).
development (see Fig. 173-1). Usually a family member had delayed growth or puberty but achieved a normal final height. The bone age is delayed, but the growth rate remains mostly within the lower limits of normal. Constitutional delay usually leads to a delay in secondary sexual development. Genetic or familial short stature (Table 173-3) refers to the stature of a child of short parents, who is expected to reach a lower than average height and yet normal for these parents. If the parents were malnourished as children, grew up in a zone of war, or suffered famine, the heights of the parents are less predictive. Although there are differences in height associated with ethnicity, the most significant difference in stature between ethnic groups is the result of nutrition.
Phenotypic features suggesting an underlying chromosomaldisorder can occur in many syndromes. These syndromes can besuspected by attending to arm spans and upper-to-lower segmentratios. Genetic syndromes often combine obesity and decreasedheight, whereas otherwise normal obese children are usuallytaller than average and have advanced skeletal development andphysical maturation (see Table 173-2). The Prader-Willi syndrome includes fetal and infantile hypotonia, small hands and feet (acromicria), postnatal acquired obesity with an insatiableappetite, developmental delay, hypogonadism, almond-shapedeyes, and abnormalities of the snRNP (small nuclear ribonucleicparticle) portion of the 15th chromosome at 15q11-q13. Mostcases have deletion of the paternal sequence, but about 20% to25% have uniparental disomy, in which both chromosomes 15derive from the mother. Laurence-Moon-Bardet-Biedl syndrome is characterized by retinitis pigmentosa, hypogonadism, and developmental delay with an autosomal dominant inheritance pattern. Laurence-Moon syndrome is associated with spastic paraplegia; Bardet-Biedl syndrome is associatedwith obesity and polydactyly. Pseudohypoparathyroidismleads to short stature and developmental delay with short fourthand fifth digits (Albright hereditary osteodystrophy phenotype),resistance to parathyroid hormone and resultant hypocalcemia,and elevated levels of serum phosphorus. Turner syndrome is characterized by a karyotype of 45XO or by a mosaic karyotypeand clinically presents with short stature, shield chest, wide-spaced nipples, wide-carrying angle of the upper extremities,high-arched palate, gonadal failure, kidney dysplasias with normal function, and aortic arch abnormalities. Affected girlsare often susceptible to autoimmune disorders.
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