Table 1

Comparison of the clinical, genetic and radiological features of the different types of acromesomelic dyplasias including the new acromesomelic dysplasia PRKG2 type (AMDP)

Features	Acromesomelic dysplasia, type Maroteaux (AMDM)	Grebe dysplasia*	Fibular hypoplasia and complex brachydactyly (Du Pan syndrome)	Acromesomelic dysplasia, Osebold-Resmondini type†	Acromesomelic dysplasia, PRKG2 type (AMDP)
OMIM	602875	200700, 609441, 201250, 603248	228900	112910	–
Gene (inheritance)	NPR2 (AR)	GDF5, BMPR1B (AR)	GDF5, BMPR1B (AR)	− (AD)	PRKG2 (P1) (AR)	PRKG2 (P2) (AR)
Short stature	+ (severe)	+ (severe)	−/+ (moderate)	+ (moderate)	+ (severe)	+ (severe)
Adult height (cm)	95–122	100–140	ND	135–160	130 (Est)	NR
Acromesomelia	+‡	+	+	+	+	+
Bowed forearm	+	+	–	+	+	+/−
Brachydactyly	+	+	+	+	+	+
Hand phalanges (hypoplasia)	+ (broad)	+ (rudimentary)	+	+(second) (3rd–5th syndactyly)	+ (broad)	+
Hyperlordosis	+	–	–	–	+	–
Talipes equinovarus	–	+	+	+	–	–
Toes	Long broad halluces	Hypoplasia (non-funcional)	Hypoplasia (knob-like)	Short, broad, sandal gap	Normal	Short, broad, sandal gap
Nail aplasia/hypoplasia	+ (fingers)	–	+ (toes)	–	–	–
Facial dysmorphism	Frontal bossing, depressed nasal ridge, short nose	–	–	–	–	Triangular face, broad nasal bridge, pointed chin, synophrys, hypertelorism and low set ears
Other features	–	Hypoplastic uterus, absent ovaries§	–	–		Hirsutism
Prenatal presentation	–	+/−	ND	+	ND	ND
Phenotype in heterozygous state	Short stature, brachydactly, mild clinical features	Brachydactyly	–	NA	–	Short stature?
Radiological features
Skull	Large, with frontal bossing	Normal	Normal	Normal	Normal
Spine	Oval-shaped vertebrae in infancy Ventral protrusion of centrally located ‘tongue’ Posterior wedging of vertebrae Short pedicles	Normal	Normal	Normal	Short pedicles Anterior beaking vertebral bodies of thoracolumbar junction
Pelvis	Acetabular notch Relative hypoplasia of base of ilia	Normal	Normal	Normal	Mild acetabular irregularity
Long tubular bones	Mesomelia (+++) with upper limbs more severely affected than lower limbs Bowed radius Dislocation/subluxation of radial head Flared metaphyses	Mesomelia (++) with relatively normal rhizomelic segments	Absent/hypoplastic fibulae Dislocated knees	Mesomelia (++/++)	Mesomelia (+) Mildly bowed radius and ulna Relatively large epiphyses Metaphyseal irregularity
Short tubular bones	Brachydactyly (+++) with relative sparing of big toes Cone-shaped epiphyses with premature fusion	Brachydactyly (++/+++) Carpal/tarsal fusions Absent ossification metacarpals, metatarsals, some carpal and tarsal bones and proximal and middle phalanges Postaxial polydactyly	Brachydactyly (++/+++) Carpal/tarsal fusions Absent ossification metacarpals, metatarsals, some carpal and tarsal bones and proximal and middle phalanges Postaxial polydactyly	Brachydactyly (+/++) Hypoplastic/absent ossification of middle phalanges of hands and feet Phalangeal synostosis Carpal and tarsal Synostosis Bipartite calcanei	Brachydactyly (+) Advanced bone age Premature fusion of epiphyses of hands and knees

*Grebe dysplasia encompassing also Hunter-Thompson dysplasia and acromesomelic dysplasia with genital anomalies (Demirhan type).
†One family described.36
‡Appears between 1 and 2 years of age.
§Described in acromesomelic dysplasia with genital anomalies (Demirhan type).
NA, not applicable as AD inheritance; ND, not described; NR, not reached adult height.